mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2024-12-23 14:15:28 +00:00
be74ebccbe
The version attribute in redirdev filters refers to the revision
of the device, not the version of the USB protocol.
Explicitly state that this is not the USB protocol and remove references
to those round version numbers that resemble USB protocol versions.
https://bugzilla.redhat.com/show_bug.cgi?id=1177237
(cherry picked from commit 76a2a5ce8b)
6033 lines
247 KiB
XML
6033 lines
247 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<body>
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<h1>Domain XML format</h1>
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<ul id="toc"></ul>
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<p>
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This section describes the XML format used to represent domains, there are
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variations on the format based on the kind of domains run and the options
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used to launch them. For hypervisor specific details consult the
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<a href="drivers.html">driver docs</a>
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</p>
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<h2><a name="elements">Element and attribute overview</a></h2>
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<p>
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The root element required for all virtual machines is
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named <code>domain</code>. It has two attributes, the
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<code>type</code> specifies the hypervisor used for running
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the domain. The allowed values are driver specific, but
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include "xen", "kvm", "qemu", "lxc" and "kqemu". The
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second attribute is <code>id</code> which is a unique
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integer identifier for the running guest machine. Inactive
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machines have no id value.
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</p>
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<h3><a name="elementsMetadata">General metadata</a></h3>
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<pre>
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<domain type='xen' id='3'>
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<name>fv0</name>
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<uuid>4dea22b31d52d8f32516782e98ab3fa0</uuid>
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<title>A short description - title - of the domain</title>
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<description>Some human readable description</description>
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<metadata>
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<app1:foo xmlns:app1="http://app1.org/app1/">..</app1:foo>
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<app2:bar xmlns:app2="http://app1.org/app2/">..</app2:bar>
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</metadata>
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...</pre>
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<dl>
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<dt><code>name</code></dt>
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<dd>The content of the <code>name</code> element provides
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a short name for the virtual machine. This name should
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consist only of alpha-numeric characters and is required
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to be unique within the scope of a single host. It is
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often used to form the filename for storing the persistent
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configuration file. <span class="since">Since 0.0.1</span></dd>
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<dt><code>uuid</code></dt>
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<dd>The content of the <code>uuid</code> element provides
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a globally unique identifier for the virtual machine.
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The format must be RFC 4122 compliant,
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eg <code>3e3fce45-4f53-4fa7-bb32-11f34168b82b</code>.
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If omitted when defining/creating a new machine, a random
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UUID is generated. It is also possible to provide the UUID
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via a <a href="#elementsSysinfo"><code>sysinfo</code></a>
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specification. <span class="since">Since 0.0.1, sysinfo
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since 0.8.7</span></dd>
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<dt><code>title</code></dt>
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<dd>The optional element <code>title</code> provides space for a
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short description of the domain. The title should not contain
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any newlines. <span class="since">Since 0.9.10</span>.</dd>
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<dt><code>description</code></dt>
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<dd>The content of the <code>description</code> element provides a
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human readable description of the virtual machine. This data is not
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used by libvirt in any way, it can contain any information the user
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wants. <span class="since">Since 0.7.2</span></dd>
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<dt><code>metadata</code></dt>
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<dd>The <code>metadata</code> node can be used by applications
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to store custom metadata in the form of XML
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nodes/trees. Applications must use custom namespaces on their
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XML nodes/trees, with only one top-level element per namespace
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(if the application needs structure, they should have
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sub-elements to their namespace
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element). <span class="since">Since 0.9.10</span></dd>
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</dl>
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<h3><a name="elementsOS">Operating system booting</a></h3>
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<p>
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There are a number of different ways to boot virtual machines
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each with their own pros and cons.
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</p>
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<h4><a name="elementsOSBIOS">BIOS bootloader</a></h4>
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<p>
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Booting via the BIOS is available for hypervisors supporting
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full virtualization. In this case the BIOS has a boot order
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priority (floppy, harddisk, cdrom, network) determining where
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to obtain/find the boot image.
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</p>
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<pre>
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...
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<os>
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<type>hvm</type>
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<loader readonly='yes' type='rom'>/usr/lib/xen/boot/hvmloader</loader>
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<nvram template='/usr/share/OVMF/OVMF_VARS.fd'>/var/lib/libvirt/nvram/guest_VARS.fd</nvram>
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<boot dev='hd'/>
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<boot dev='cdrom'/>
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<bootmenu enable='yes' timeout='3000'/>
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<smbios mode='sysinfo'/>
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<bios useserial='yes' rebootTimeout='0'/>
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</os>
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...</pre>
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<dl>
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<dt><code>type</code></dt>
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<dd>The content of the <code>type</code> element specifies the
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type of operating system to be booted in the virtual machine.
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<code>hvm</code> indicates that the OS is one designed to run
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on bare metal, so requires full virtualization. <code>linux</code>
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(badly named!) refers to an OS that supports the Xen 3 hypervisor
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guest ABI. There are also two optional attributes, <code>arch</code>
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specifying the CPU architecture to virtualization,
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and <code>machine</code> referring to the machine
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type. The <a href="formatcaps.html">Capabilities XML</a>
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provides details on allowed values for
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these. <span class="since">Since 0.0.1</span></dd>
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<dt><code>loader</code></dt>
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<dd>The optional <code>loader</code> tag refers to a firmware blob
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used to assist the domain creation process. It is used by Xen
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fully virtualized domains as well as setting the QEMU BIOS file
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path for QEMU/KVM domains. <span class="since">Xen since 0.1.0,
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QEMU/KVM since 0.9.12</span> Then, <span class="since">since
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1.2.8</span> it's possible for the element to have two
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optional attributes: <code>readonly</code> (accepted values are
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<code>yes</code> and <code>no</code>) to reflect the fact that the
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image should be writable or read-only. The second attribute
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<code>type</code> accepts values <code>rom</code> and
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<code>pflash</code>. It tells the hypervisor where in the guest
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memory the file should be mapped. For instance, if the loader
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path points to an UEFI image, <code>type</code> should be
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<code>pflash</code>.</dd>
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<dt><code>nvram</code></dt>
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<dd>Some UEFI firmwares may want to use a non-volatile memory to store
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some variables. In the host, this is represented as a file and the path
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to the file is stored in this element. Moreover, when the domain is
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started up libvirt copies so called master NVRAM store file defined
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in <code>qemu.conf</code>. If needed, the <code>template</code>
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attribute can be used to per domain override map of master NVRAM stores
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from the config file. Note, that for transient domains if the NVRAM file
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has been created by libvirt it is left behind and it is management
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application's responsibility to save and remove file (if needed to be
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persistent). <span class="since">Since 1.2.8</span></dd>
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<dt><code>boot</code></dt>
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<dd>The <code>dev</code> attribute takes one of the values "fd", "hd",
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"cdrom" or "network" and is used to specify the next boot device
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to consider. The <code>boot</code> element can be repeated multiple
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times to setup a priority list of boot devices to try in turn.
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Multiple devices of the same type are sorted according to their
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targets while preserving the order of buses. After defining the
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domain, its XML configuration returned by libvirt (through
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virDomainGetXMLDesc) lists devices in the sorted order. Once sorted,
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the first device is marked as bootable. Thus, e.g., a domain
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configured to boot from "hd" with vdb, hda, vda, and hdc disks
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assigned to it will boot from vda (the sorted list is vda, vdb, hda,
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hdc). Similar domain with hdc, vda, vdb, and hda disks will boot from
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hda (sorted disks are: hda, hdc, vda, vdb). It can be tricky to
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configure in the desired way, which is why per-device boot elements
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(see <a href="#elementsDisks">disks</a>,
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<a href="#elementsNICS">network interfaces</a>, and
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<a href="#elementsHostDev">USB and PCI devices</a> sections below) were
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introduced and they are the preferred way providing full control over
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booting order. The <code>boot</code> element and per-device boot
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elements are mutually exclusive. <span class="since">Since 0.1.3,
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per-device boot since 0.8.8</span>
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</dd>
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<dt><code>smbios</code></dt>
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<dd>How to populate SMBIOS information visible in the guest.
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The <code>mode</code> attribute must be specified, and is either
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"emulate" (let the hypervisor generate all values), "host" (copy
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all of Block 0 and Block 1, except for the UUID, from the host's
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SMBIOS values;
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the <a href="html/libvirt-libvirt-host.html#virConnectGetSysinfo">
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<code>virConnectGetSysinfo</code></a> call can be
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used to see what values are copied), or "sysinfo" (use the values in
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the <a href="#elementsSysinfo">sysinfo</a> element). If not
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specified, the hypervisor default is used. <span class="since">
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Since 0.8.7</span>
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</dd>
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</dl>
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<p>Up till here the BIOS/UEFI configuration knobs are generic enough to
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be implemented by majority (if not all) firmwares out there. However,
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from now on not every single setting makes sense to all firmwares. For
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instance, <code>rebootTimeout</code> doesn't make sense for UEFI,
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<code>useserial</code> might not be usable with a BIOS firmware that
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doesn't produce any output onto serial line, etc. Moreover, firmwares
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don't usually export their capabilities for libvirt (or users) to check.
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And the set of their capabilities can change with every new release.
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Hence users are advised to try the settings they use before relying on
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them in production.</p>
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<dl>
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<dt><code>bootmenu</code></dt>
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<dd> Whether or not to enable an interactive boot menu prompt on guest
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startup. The <code>enable</code> attribute can be either "yes" or "no".
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If not specified, the hypervisor default is used. <span class="since">
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Since 0.8.3</span>
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Additional attribute <code>timeout</code> takes the number of milliseconds
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the boot menu should wait until it times out. Allowed values are numbers
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in range [0, 65535] inclusive and it is ignored unless <code>enable</code>
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is set to "yes". <span class="since">Since 1.2.8</span>
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</dd>
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<dt><code>bios</code></dt>
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<dd>This element has attribute <code>useserial</code> with possible
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values <code>yes</code> or <code>no</code>. It enables or disables
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Serial Graphics Adapter which allows users to see BIOS messages
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on a serial port. Therefore, one needs to have
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<a href="#elementCharSerial">serial port</a> defined.
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<span class="since">Since 0.9.4</span>.
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<span class="since">Since 0.10.2 (QEMU only)</span> there is
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another attribute, <code>rebootTimeout</code> that controls
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whether and after how long the guest should start booting
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again in case the boot fails (according to BIOS). The value is
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in milliseconds with maximum of <code>65535</code> and special
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value <code>-1</code> disables the reboot.
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</dd>
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</dl>
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<h4><a name="elementsOSBootloader">Host bootloader</a></h4>
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<p>
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Hypervisors employing paravirtualization do not usually emulate
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a BIOS, and instead the host is responsible to kicking off the
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operating system boot. This may use a pseudo-bootloader in the
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host to provide an interface to choose a kernel for the guest.
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An example is <code>pygrub</code> with Xen. The Bhyve hypervisor
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also uses a host bootloader, either <code>bhyveload</code> or
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<code>grub-bhyve</code>.
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</p>
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<pre>
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...
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<bootloader>/usr/bin/pygrub</bootloader>
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<bootloader_args>--append single</bootloader_args>
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...</pre>
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<dl>
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<dt><code>bootloader</code></dt>
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<dd>The content of the <code>bootloader</code> element provides
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a fully qualified path to the bootloader executable in the
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host OS. This bootloader will be run to choose which kernel
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to boot. The required output of the bootloader is dependent
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on the hypervisor in use. <span class="since">Since 0.1.0</span></dd>
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<dt><code>bootloader_args</code></dt>
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<dd>The optional <code>bootloader_args</code> element allows
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command line arguments to be passed to the bootloader.
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<span class="since">Since 0.2.3</span>
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</dd>
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</dl>
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<h4><a name="elementsOSKernel">Direct kernel boot</a></h4>
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<p>
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When installing a new guest OS it is often useful to boot directly
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from a kernel and initrd stored in the host OS, allowing command
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line arguments to be passed directly to the installer. This capability
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is usually available for both para and full virtualized guests.
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</p>
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<pre>
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...
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<os>
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<type>hvm</type>
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<loader>/usr/lib/xen/boot/hvmloader</loader>
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<kernel>/root/f8-i386-vmlinuz</kernel>
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<initrd>/root/f8-i386-initrd</initrd>
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<cmdline>console=ttyS0 ks=http://example.com/f8-i386/os/</cmdline>
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<dtb>/root/ppc.dtb</dtb>
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</os>
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...</pre>
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<dl>
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<dt><code>type</code></dt>
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<dd>This element has the same semantics as described earlier in the
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<a href="#elementsOSBIOS">BIOS boot section</a></dd>
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<dt><code>loader</code></dt>
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<dd>This element has the same semantics as described earlier in the
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<a href="#elementsOSBIOS">BIOS boot section</a></dd>
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<dt><code>kernel</code></dt>
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<dd>The contents of this element specify the fully-qualified path
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to the kernel image in the host OS.</dd>
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<dt><code>initrd</code></dt>
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<dd>The contents of this element specify the fully-qualified path
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to the (optional) ramdisk image in the host OS.</dd>
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<dt><code>cmdline</code></dt>
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<dd>The contents of this element specify arguments to be passed to
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the kernel (or installer) at boot time. This is often used to
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specify an alternate primary console (eg serial port), or the
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installation media source / kickstart file</dd>
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<dt><code>dtb</code></dt>
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<dd>The contents of this element specify the fully-qualified path
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to the (optional) device tree binary (dtb) image in the host OS.
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<span class="since">Since 1.0.4</span></dd>
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</dl>
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<h4><a name="elementsOSContainer">Container boot</a></h4>
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<p>
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When booting a domain using container based virtualization, instead
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of a kernel / boot image, a path to the init binary is required, using
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the <code>init</code> element. By default this will be launched with
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no arguments. To specify the initial argv, use the <code>initarg</code>
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element, repeated as many time as is required. The <code>cmdline</code>
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element, if set will be used to provide an equivalent to <code>/proc/cmdline</code>
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but will not affect init argv.
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</p>
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<pre>
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<os>
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<type arch='x86_64'>exe</type>
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<init>/bin/systemd</init>
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<initarg>--unit</initarg>
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<initarg>emergency.service</initarg>
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</os>
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</pre>
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|
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<p>
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If you want to enable user namespace, set the <code>idmap</code> element.
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The <code>uid</code> and <code>gid</code> elements have three attributes:
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</p>
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|
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<dl>
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<dt><code>start</code></dt>
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<dd>First user ID in container. It must be '0'.</dd>
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<dt><code>target</code></dt>
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<dd>The first user ID in container will be mapped to this target user
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ID in host.</dd>
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<dt><code>count</code></dt>
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<dd>How many users in container are allowed to map to host's user.</dd>
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</dl>
|
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|
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<pre>
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<idmap>
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<uid start='0' target='1000' count='10'/>
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<gid start='0' target='1000' count='10'/>
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</idmap>
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</pre>
|
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|
|
|
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<h3><a name="elementsSysinfo">SMBIOS System Information</a></h3>
|
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|
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<p>
|
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Some hypervisors allow control over what system information is
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presented to the guest (for example, SMBIOS fields can be
|
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populated by a hypervisor and inspected via
|
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the <code>dmidecode</code> command in the guest). The
|
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optional <code>sysinfo</code> element covers all such categories
|
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of information. <span class="since">Since 0.8.7</span>
|
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</p>
|
|
|
|
<pre>
|
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...
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<os>
|
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<smbios mode='sysinfo'/>
|
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...
|
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</os>
|
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<sysinfo type='smbios'>
|
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<bios>
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<entry name='vendor'>LENOVO</entry>
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</bios>
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<system>
|
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<entry name='manufacturer'>Fedora</entry>
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<entry name='product'>Virt-Manager</entry>
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<entry name='version'>0.9.4</entry>
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</system>
|
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</sysinfo>
|
|
...</pre>
|
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|
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<p>
|
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The <code>sysinfo</code> element has a mandatory
|
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attribute <code>type</code> that determine the layout of
|
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sub-elements, with supported values of:
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</p>
|
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|
|
<dl>
|
|
<dt><code>smbios</code></dt>
|
|
<dd>Sub-elements call out specific SMBIOS values, which will
|
|
affect the guest if used in conjunction with
|
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the <code>smbios</code> sub-element of
|
|
the <a href="#elementsOS"><code>os</code></a> element. Each
|
|
sub-element of <code>sysinfo</code> names a SMBIOS block, and
|
|
within those elements can be a list of <code>entry</code>
|
|
elements that describe a field within the block. The following
|
|
blocks and entries are recognized:
|
|
<dl>
|
|
<dt><code>bios</code></dt>
|
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<dd>
|
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This is block 0 of SMBIOS, with entry names drawn from:
|
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<dl>
|
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<dt><code>vendor</code></dt>
|
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<dd>BIOS Vendor's Name</dd>
|
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<dt><code>version</code></dt>
|
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<dd>BIOS Version</dd>
|
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<dt><code>date</code></dt>
|
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<dd>BIOS release date. If supplied, is in either mm/dd/yy or
|
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mm/dd/yyyy format. If the year portion of the string is
|
|
two digits, the year is assumed to be 19yy.</dd>
|
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<dt><code>release</code></dt>
|
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<dd>System BIOS Major and Minor release number values
|
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concatenated together as one string separated by
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a period, for example, 10.22.</dd>
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</dl>
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</dd>
|
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<dt><code>system</code></dt>
|
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<dd>
|
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This is block 1 of SMBIOS, with entry names drawn from:
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<dl>
|
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<dt><code>manufacturer</code></dt>
|
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<dd>Manufacturer of BIOS</dd>
|
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<dt><code>product</code></dt>
|
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<dd>Product Name</dd>
|
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<dt><code>version</code></dt>
|
|
<dd>Version of the product</dd>
|
|
<dt><code>serial</code></dt>
|
|
<dd>Serial number</dd>
|
|
<dt><code>uuid</code></dt>
|
|
<dd>Universal Unique ID number. If this entry is provided
|
|
alongside a top-level
|
|
<a href="#elementsMetadata"><code>uuid</code></a> element,
|
|
then the two values must match.</dd>
|
|
<dt><code>sku</code></dt>
|
|
<dd>SKU number to identify a particular configuration.</dd>
|
|
<dt><code>family</code></dt>
|
|
<dd>Identify the family a particular computer belongs to.</dd>
|
|
</dl>
|
|
NB: Incorrectly supplied entries in either the <code>bios</code>
|
|
or <code>system</code> blocks will be ignored without error.
|
|
Other than <code>uuid</code> validation and <code>date</code>
|
|
format checking, all values are passed as strings to the
|
|
hypervisor driver.
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h3><a name="elementsCPUAllocation">CPU Allocation</a></h3>
|
|
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<vcpu placement='static' cpuset="1-4,^3,6" current="1">2</vcpu>
|
|
...
|
|
</domain>
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>vcpu</code></dt>
|
|
<dd>The content of this element defines the maximum number of virtual
|
|
CPUs allocated for the guest OS, which must be between 1 and
|
|
the maximum supported by the hypervisor.
|
|
<dl>
|
|
<dt><code>cpuset</code></dt>
|
|
<dd>
|
|
The optional attribute <code>cpuset</code> is a comma-separated
|
|
list of physical CPU numbers that domain process and virtual CPUs
|
|
can be pinned to by default. (NB: The pinning policy of domain
|
|
process and virtual CPUs can be specified separately by
|
|
<code>cputune</code>. If the attribute <code>emulatorpin</code>
|
|
of <code>cputune</code> is specified, the <code>cpuset</code>
|
|
specified by <code>vcpu</code> here will be ignored. Similarly,
|
|
for virtual CPUs which have the <code>vcpupin</code> specified,
|
|
the <code>cpuset</code> specified by <code>cpuset</code> here
|
|
will be ignored. For virtual CPUs which don't have
|
|
<code>vcpupin</code> specified, each will be pinned to the physical
|
|
CPUs specified by <code>cpuset</code> here).
|
|
Each element in that list is either a single CPU number,
|
|
a range of CPU numbers, or a caret followed by a CPU number to
|
|
be excluded from a previous range.
|
|
<span class="since">Since 0.4.4</span>
|
|
</dd>
|
|
<dt><code>current</code></dt>
|
|
<dd>
|
|
The optional attribute <code>current</code> can
|
|
be used to specify whether fewer than the maximum number of
|
|
virtual CPUs should be enabled.
|
|
<span class="since">Since 0.8.5</span>
|
|
</dd>
|
|
<dt><code>placement</code></dt>
|
|
<dd>
|
|
The optional attribute <code>placement</code> can be used to
|
|
indicate the CPU placement mode for domain process. The value can
|
|
be either "static" or "auto", but defaults to <code>placement</code>
|
|
of <code>numatune</code> or "static" if <code>cpuset</code> is
|
|
specified. Using "auto" indicates the domain process will be pinned
|
|
to the advisory nodeset from querying numad and the value of
|
|
attribute <code>cpuset</code> will be ignored if it's specified.
|
|
If both <code>cpuset</code> and <code>placement</code> are not
|
|
specified or if <code>placement</code> is "static", but no
|
|
<code>cpuset</code> is specified, the domain process will be
|
|
pinned to all the available physical CPUs.
|
|
<span class="since">Since 0.9.11 (QEMU and KVM only)</span>
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h3><a name="elementsIOThreadsAllocation">IOThreads Allocation</a></h3>
|
|
<p>
|
|
IOThreads are dedicated event loop threads for supported disk
|
|
devices to perform block I/O requests in order to improve
|
|
scalability especially on an SMP host/guest with many LUNs.
|
|
<span class="since">Since 1.2.8 (QEMU only)</span>
|
|
</p>
|
|
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<iothreads>4</iothreads>
|
|
...
|
|
</domain>
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>iothreads</code></dt>
|
|
<dd>
|
|
The content of this optional element defines the number
|
|
of IOThreads to be assigned to the domain for use by
|
|
virtio-blk-pci and virtio-blk-ccw target storage devices. There
|
|
should be only 1 or 2 IOThreads per host CPU. There may be more
|
|
than one supported device assigned to each IOThread.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h3><a name="elementsCPUTuning">CPU Tuning</a></h3>
|
|
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<cputune>
|
|
<vcpupin vcpu="0" cpuset="1-4,^2"/>
|
|
<vcpupin vcpu="1" cpuset="0,1"/>
|
|
<vcpupin vcpu="2" cpuset="2,3"/>
|
|
<vcpupin vcpu="3" cpuset="0,4"/>
|
|
<emulatorpin cpuset="1-3"/>
|
|
<iothreadpin iothread="1" cpuset="5,6"/>
|
|
<iothreadpin iothread="2" cpuset="7,8"/>
|
|
<shares>2048</shares>
|
|
<period>1000000</period>
|
|
<quota>-1</quota>
|
|
<emulator_period>1000000</emulator_period>
|
|
<emulator_quota>-1</emulator_quota>
|
|
<vcpusched vcpus='0-4,^3' scheduler='fifo' priority='1'/>
|
|
<iothreadsched iothreads='2' scheduler='batch'/>
|
|
</cputune>
|
|
...
|
|
</domain>
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>cputune</code></dt>
|
|
<dd>
|
|
The optional <code>cputune</code> element provides details
|
|
regarding the cpu tunable parameters for the domain.
|
|
<span class="since">Since 0.9.0</span>
|
|
</dd>
|
|
<dt><code>vcpupin</code></dt>
|
|
<dd>
|
|
The optional <code>vcpupin</code> element specifies which of host's
|
|
physical CPUs the domain VCPU will be pinned to. If this is omitted,
|
|
and attribute <code>cpuset</code> of element <code>vcpu</code> is
|
|
not specified, the vCPU is pinned to all the physical CPUs by default.
|
|
It contains two required attributes, the attribute <code>vcpu</code>
|
|
specifies vcpu id, and the attribute <code>cpuset</code> is same as
|
|
attribute <code>cpuset</code> of element <code>vcpu</code>.
|
|
(NB: Only qemu driver support)
|
|
<span class="since">Since 0.9.0</span>
|
|
</dd>
|
|
<dt><code>emulatorpin</code></dt>
|
|
<dd>
|
|
The optional <code>emulatorpin</code> element specifies which of host
|
|
physical CPUs the "emulator", a subset of a domain not including vcpu
|
|
or iothreads will be pinned to. If this is omitted, and attribute
|
|
<code>cpuset</code> of element <code>vcpu</code> is not specified,
|
|
"emulator" is pinned to all the physical CPUs by default. It contains
|
|
one required attribute <code>cpuset</code> specifying which physical
|
|
CPUs to pin to.
|
|
</dd>
|
|
<dt><code>iothreadpin</code></dt>
|
|
<dd>
|
|
The optional <code>iothreadpin</code> element specifies which of host
|
|
physical CPUs the IOThreads will be pinned to. If this is omitted
|
|
and attribute <code>cpuset</code> of element <code>vcpu</code> is
|
|
not specified, the IOThreads are pinned to all the physical CPUs
|
|
by default. There are two required attributes, the attribute
|
|
<code>iothread</code> specifies the IOThread id and the attribute
|
|
<code>cpuset</code> specifying which physical CPUs to pin to. The
|
|
<code>iothread</code> value begins at "1" through the number of
|
|
<a href="#elementsIOThreadsAllocation"><code>iothreads</code></a>
|
|
allocated to the domain. A value of "0" is not permitted.
|
|
<span class="since">Since 1.2.9</span>
|
|
</dd>
|
|
<dt><code>shares</code></dt>
|
|
<dd>
|
|
The optional <code>shares</code> element specifies the proportional
|
|
weighted share for the domain. If this is omitted, it defaults to
|
|
the OS provided defaults. NB, There is no unit for the value,
|
|
it's a relative measure based on the setting of other VM,
|
|
e.g. A VM configured with value
|
|
2048 will get twice as much CPU time as a VM configured with value 1024.
|
|
<span class="since">Since 0.9.0</span>
|
|
</dd>
|
|
<dt><code>period</code></dt>
|
|
<dd>
|
|
The optional <code>period</code> element specifies the enforcement
|
|
interval(unit: microseconds). Within <code>period</code>, each vcpu of
|
|
the domain will not be allowed to consume more than <code>quota</code>
|
|
worth of runtime. The value should be in range [1000, 1000000]. A period
|
|
with value 0 means no value.
|
|
<span class="since">Only QEMU driver support since 0.9.4, LXC since
|
|
0.9.10</span>
|
|
</dd>
|
|
<dt><code>quota</code></dt>
|
|
<dd>
|
|
The optional <code>quota</code> element specifies the maximum allowed
|
|
bandwidth(unit: microseconds). A domain with <code>quota</code> as any
|
|
negative value indicates that the domain has infinite bandwidth, which
|
|
means that it is not bandwidth controlled. The value should be in range
|
|
[1000, 18446744073709551] or less than 0. A quota with value 0 means no
|
|
value. You can use this feature to ensure that all vcpus run at the same
|
|
speed.
|
|
<span class="since">Only QEMU driver support since 0.9.4, LXC since
|
|
0.9.10</span>
|
|
</dd>
|
|
|
|
<dt><code>emulator_period</code></dt>
|
|
<dd>
|
|
The optional <code>emulator_period</code> element specifies the enforcement
|
|
interval(unit: microseconds). Within <code>emulator_period</code>, emulator
|
|
threads(those excluding vcpus) of the domain will not be allowed to consume
|
|
more than <code>emulator_quota</code> worth of runtime. The value should be
|
|
in range [1000, 1000000]. A period with value 0 means no value.
|
|
<span class="since">Only QEMU driver support since 0.10.0</span>
|
|
</dd>
|
|
<dt><code>emulator_quota</code></dt>
|
|
<dd>
|
|
The optional <code>emulator_quota</code> element specifies the maximum
|
|
allowed bandwidth(unit: microseconds) for domain's emulator threads(those
|
|
excluding vcpus). A domain with <code>emulator_quota</code> as any negative
|
|
value indicates that the domain has infinite bandwidth for emulator threads
|
|
(those excluding vcpus), which means that it is not bandwidth controlled.
|
|
The value should be in range [1000, 18446744073709551] or less than 0. A
|
|
quota with value 0 means no value.
|
|
<span class="since">Only QEMU driver support since 0.10.0</span>
|
|
</dd>
|
|
|
|
<dt><code>vcpusched</code> and <code>iothreadsched</code></dt>
|
|
<dd>
|
|
The optional <code>vcpusched</code> elements specifies the scheduler
|
|
type (values <code>batch</code>, <code>idle</code>, <code>fifo</code>,
|
|
<code>rr</code>) for particular vCPU/IOThread threads (based on
|
|
<code>vcpus</code> and <code>iothreads</code>, leaving out
|
|
<code>vcpus</code>/<code>iothreads</code> sets the default). For
|
|
real-time schedulers (<code>fifo</code>, <code>rr</code>), priority must
|
|
be specified as well (and is ignored for non-real-time ones). The value
|
|
range for the priority depends on the host kernel (usually 1-99).
|
|
<span class="since">Since 1.2.13</span>
|
|
</dd>
|
|
|
|
</dl>
|
|
|
|
|
|
<h3><a name="elementsMemoryAllocation">Memory Allocation</a></h3>
|
|
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<memory unit='KiB'>524288</memory>
|
|
<currentMemory unit='KiB'>524288</currentMemory>
|
|
...
|
|
</domain>
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>memory</code></dt>
|
|
<dd>The maximum allocation of memory for the guest at boot time.
|
|
The units for this value are determined by the optional
|
|
attribute <code>unit</code>, which defaults to "KiB"
|
|
(kibibytes, 2<sup>10</sup> or blocks of 1024 bytes). Valid
|
|
units are "b" or "bytes" for bytes, "KB" for kilobytes
|
|
(10<sup>3</sup> or 1,000 bytes), "k" or "KiB" for kibibytes
|
|
(1024 bytes), "MB" for megabytes (10<sup>6</sup> or 1,000,000
|
|
bytes), "M" or "MiB" for mebibytes (2<sup>20</sup> or
|
|
1,048,576 bytes), "GB" for gigabytes (10<sup>9</sup> or
|
|
1,000,000,000 bytes), "G" or "GiB" for gibibytes
|
|
(2<sup>30</sup> or 1,073,741,824 bytes), "TB" for terabytes
|
|
(10<sup>12</sup> or 1,000,000,000,000 bytes), or "T" or "TiB"
|
|
for tebibytes (2<sup>40</sup> or 1,099,511,627,776 bytes).
|
|
However, the value will be rounded up to the nearest kibibyte
|
|
by libvirt, and may be further rounded to the granularity
|
|
supported by the hypervisor. Some hypervisors also enforce a
|
|
minimum, such as 4000KiB.
|
|
|
|
In the case of crash, optional attribute <code>dumpCore</code>
|
|
can be used to control whether the guest memory should be
|
|
included in the generated coredump or not (values "on", "off").
|
|
|
|
<span class='since'><code>unit</code> since 0.9.11</span>,
|
|
<span class='since'><code>dumpCore</code> since 0.10.2
|
|
(QEMU only)</span></dd>
|
|
<dt><code>currentMemory</code></dt>
|
|
<dd>The actual allocation of memory for the guest. This value can
|
|
be less than the maximum allocation, to allow for ballooning
|
|
up the guests memory on the fly. If this is omitted, it defaults
|
|
to the same value as the <code>memory</code> element.
|
|
The <code>unit</code> attribute behaves the same as
|
|
for <code>memory</code>.</dd>
|
|
</dl>
|
|
|
|
|
|
<h3><a name="elementsMemoryBacking">Memory Backing</a></h3>
|
|
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<memoryBacking>
|
|
<hugepages>
|
|
<page size="1" unit="G" nodeset="0-3,5"/>
|
|
<page size="2" unit="M" nodeset="4"/>
|
|
</hugepages>
|
|
<nosharepages/>
|
|
<locked/>
|
|
</memoryBacking>
|
|
...
|
|
</domain>
|
|
</pre>
|
|
|
|
<p>The optional <code>memoryBacking</code> element may contain several
|
|
elements that influence how virtual memory pages are backed by host
|
|
pages.</p>
|
|
|
|
<dl>
|
|
<dt><code>hugepages</code></dt>
|
|
<dd>This tells the hypervisor that the guest should have its memory
|
|
allocated using hugepages instead of the normal native page size.
|
|
<span class='since'>Since 1.2.5</span> it's possible to set hugepages
|
|
more specifically per numa node. The <code>page</code> element is
|
|
introduced. It has one compulsory attribute <code>size</code> which
|
|
specifies which hugepages should be used (especially useful on systems
|
|
supporting hugepages of different sizes). The default unit for the
|
|
<code>size</code> attribute is kilobytes (multiplier of 1024). If you
|
|
want to use different unit, use optional <code>unit</code> attribute.
|
|
For systems with NUMA, the optional <code>nodeset</code> attribute may
|
|
come handy as it ties given guest's NUMA nodes to certain hugepage
|
|
sizes. From the example snippet, one gigabyte hugepages are used for
|
|
every NUMA node except node number four. For the correct syntax see
|
|
<a href="#elementsNUMATuning">this</a>.</dd>
|
|
<dt><code>nosharepages</code></dt>
|
|
<dd>Instructs hypervisor to disable shared pages (memory merge, KSM) for
|
|
this domain. <span class="since">Since 1.0.6</span></dd>
|
|
<dt><code>locked</code></dt>
|
|
<dd>When set and supported by the hypervisor, memory pages belonging
|
|
to the domain will be locked in host's memory and the host will not
|
|
be allowed to swap them out. For QEMU/KVM this requires
|
|
<code>hard_limit</code> <a href="#elementsMemoryTuning">memory tuning</a>
|
|
element to be used and set to the maximum memory configured for the
|
|
domain plus any memory consumed by the QEMU process itself.
|
|
<span class="since">Since 1.0.6</span></dd>
|
|
</dl>
|
|
|
|
|
|
<h3><a name="elementsMemoryTuning">Memory Tuning</a></h3>
|
|
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<memtune>
|
|
<hard_limit unit='G'>1</hard_limit>
|
|
<soft_limit unit='M'>128</soft_limit>
|
|
<swap_hard_limit unit='G'>2</swap_hard_limit>
|
|
<min_guarantee unit='bytes'>67108864</min_guarantee>
|
|
</memtune>
|
|
...
|
|
</domain>
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>memtune</code></dt>
|
|
<dd> The optional <code>memtune</code> element provides details
|
|
regarding the memory tunable parameters for the domain. If this is
|
|
omitted, it defaults to the OS provided defaults. For QEMU/KVM, the
|
|
parameters are applied to the QEMU process as a whole. Thus, when
|
|
counting them, one needs to add up guest RAM, guest video RAM, and
|
|
some memory overhead of QEMU itself. The last piece is hard to
|
|
determine so one needs guess and try. For each tunable, it
|
|
is possible to designate which unit the number is in on
|
|
input, using the same values as
|
|
for <code><memory></code>. For backwards
|
|
compatibility, output is always in
|
|
KiB. <span class='since'><code>unit</code>
|
|
since 0.9.11</span></dd>
|
|
<dt><code>hard_limit</code></dt>
|
|
<dd> The optional <code>hard_limit</code> element is the maximum memory
|
|
the guest can use. The units for this value are kibibytes (i.e. blocks
|
|
of 1024 bytes). <strong>However, users of QEMU and KVM are strongly
|
|
advised not to set this limit as domain may get killed by the kernel
|
|
if the guess is too low. To determine the memory needed for a process
|
|
to run is an
|
|
<a href="http://en.wikipedia.org/wiki/Undecidable_problem">
|
|
undecidable problem</a>.</strong></dd>
|
|
<dt><code>soft_limit</code></dt>
|
|
<dd> The optional <code>soft_limit</code> element is the memory limit to
|
|
enforce during memory contention. The units for this value are
|
|
kibibytes (i.e. blocks of 1024 bytes)</dd>
|
|
<dt><code>swap_hard_limit</code></dt>
|
|
<dd> The optional <code>swap_hard_limit</code> element is the maximum
|
|
memory plus swap the guest can use. The units for this value are
|
|
kibibytes (i.e. blocks of 1024 bytes). This has to be more than
|
|
hard_limit value provided</dd>
|
|
<dt><code>min_guarantee</code></dt>
|
|
<dd> The optional <code>min_guarantee</code> element is the guaranteed
|
|
minimum memory allocation for the guest. The units for this value are
|
|
kibibytes (i.e. blocks of 1024 bytes). This element is only supported
|
|
by VMware ESX and OpenVZ drivers.</dd>
|
|
</dl>
|
|
|
|
|
|
<h3><a name="elementsNUMATuning">NUMA Node Tuning</a></h3>
|
|
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<numatune>
|
|
<memory mode="strict" nodeset="1-4,^3"/>
|
|
<memnode cellid="0" mode="strict" nodeset="1"/>
|
|
<memnode cellid="2" mode="preferred" nodeset="2"/>
|
|
</numatune>
|
|
...
|
|
</domain>
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>numatune</code></dt>
|
|
<dd>
|
|
The optional <code>numatune</code> element provides details of
|
|
how to tune the performance of a NUMA host via controlling NUMA policy
|
|
for domain process. NB, only supported by QEMU driver.
|
|
<span class='since'>Since 0.9.3</span>
|
|
</dd>
|
|
<dt><code>memory</code></dt>
|
|
<dd>
|
|
The optional <code>memory</code> element specifies how to allocate memory
|
|
for the domain process on a NUMA host. It contains several optional
|
|
attributes. Attribute <code>mode</code> is either 'interleave',
|
|
'strict', or 'preferred', defaults to 'strict'. Attribute
|
|
<code>nodeset</code> specifies the NUMA nodes, using the same syntax as
|
|
attribute <code>cpuset</code> of element <code>vcpu</code>. Attribute
|
|
<code>placement</code> (<span class='since'>since 0.9.12</span>) can be
|
|
used to indicate the memory placement mode for domain process, its value
|
|
can be either "static" or "auto", defaults to <code>placement</code> of
|
|
<code>vcpu</code>, or "static" if <code>nodeset</code> is specified.
|
|
"auto" indicates the domain process will only allocate memory from the
|
|
advisory nodeset returned from querying numad, and the value of attribute
|
|
<code>nodeset</code> will be ignored if it's specified.
|
|
|
|
If <code>placement</code> of <code>vcpu</code> is 'auto', and
|
|
<code>numatune</code> is not specified, a default <code>numatune</code>
|
|
with <code>placement</code> 'auto' and <code>mode</code> 'strict' will
|
|
be added implicitly.
|
|
|
|
<span class='since'>Since 0.9.3</span>
|
|
</dd>
|
|
<dt><code>memnode</code></dt>
|
|
<dd>
|
|
Optional <code>memnode</code> elements can specify memory allocation
|
|
policies per each guest NUMA node. For those nodes having no
|
|
corresponding <code>memnode</code> element, the default from
|
|
element <code>memory</code> will be used. Attribute <code>cellid</code>
|
|
addresses guest NUMA node for which the settings are applied.
|
|
Attributes <code>mode</code> and <code>nodeset</code> have the same
|
|
meaning and syntax as in <code>memory</code> element.
|
|
|
|
This setting is not compatible with automatic placement.
|
|
<span class='since'>QEMU Since 1.2.7</span>
|
|
</dd>
|
|
</dl>
|
|
|
|
|
|
<h3><a name="elementsBlockTuning">Block I/O Tuning</a></h3>
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<blkiotune>
|
|
<weight>800</weight>
|
|
<device>
|
|
<path>/dev/sda</path>
|
|
<weight>1000</weight>
|
|
</device>
|
|
<device>
|
|
<path>/dev/sdb</path>
|
|
<weight>500</weight>
|
|
</device>
|
|
</blkiotune>
|
|
...
|
|
</domain>
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>blkiotune</code></dt>
|
|
<dd> The optional <code>blkiotune</code> element provides the ability
|
|
to tune Blkio cgroup tunable parameters for the domain. If this is
|
|
omitted, it defaults to the OS provided
|
|
defaults. <span class="since">Since 0.8.8</span></dd>
|
|
<dt><code>weight</code></dt>
|
|
<dd> The optional <code>weight</code> element is the overall I/O
|
|
weight of the guest. The value should be in the range [100,
|
|
1000]. After kernel 2.6.39, the value could be in the
|
|
range [10, 1000].</dd>
|
|
<dt><code>device</code></dt>
|
|
<dd>The domain may have multiple <code>device</code> elements
|
|
that further tune the weights for each host block device in
|
|
use by the domain. Note that
|
|
multiple <a href="#elementsDisks">guest disks</a> can share a
|
|
single host block device, if they are backed by files within
|
|
the same host file system, which is why this tuning parameter
|
|
is at the global domain level rather than associated with each
|
|
guest disk device (contrast this to
|
|
the <a href="#elementsDisks"><code><iotune></code></a>
|
|
element which can apply to an
|
|
individual <code><disk></code>).
|
|
Each <code>device</code> element has two
|
|
mandatory sub-elements, <code>path</code> describing the
|
|
absolute path of the device, and <code>weight</code> giving
|
|
the relative weight of that device, in the range [100,
|
|
1000]. After kernel 2.6.39, the value could be in the
|
|
range [10, 1000].<span class="since">Since 0.9.8</span></dd>
|
|
</dl>
|
|
|
|
|
|
<h3><a name="resPartition">Resource partitioning</a></h3>
|
|
|
|
<p>
|
|
Hypervisors may allow for virtual machines to be placed into
|
|
resource partitions, potentially with nesting of said partitions.
|
|
The <code>resource</code> element groups together configuration
|
|
related to resource partitioning. It currently supports a child
|
|
element <code>partition</code> whose content defines the path
|
|
of the resource partition in which to place the domain. If no
|
|
partition is listed, then the domain will be placed in a default
|
|
partition. It is the responsibility of the app/admin to ensure
|
|
that the partition exists prior to starting the guest. Only the
|
|
(hypervisor specific) default partition can be assumed to exist
|
|
by default.
|
|
</p>
|
|
<pre>
|
|
...
|
|
<resource>
|
|
<partition>/virtualmachines/production</partition>
|
|
</resource>
|
|
...
|
|
</pre>
|
|
|
|
<p>
|
|
Resource partitions are currently supported by the QEMU and
|
|
LXC drivers, which map partition paths to cgroups directories,
|
|
in all mounted controllers. <span class="since">Since 1.0.5</span>
|
|
</p>
|
|
|
|
<h3><a name="elementsCPU">CPU model and topology</a></h3>
|
|
|
|
<p>
|
|
Requirements for CPU model, its features and topology can be specified
|
|
using the following collection of elements.
|
|
<span class="since">Since 0.7.5</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<cpu match='exact'>
|
|
<model fallback='allow'>core2duo</model>
|
|
<vendor>Intel</vendor>
|
|
<topology sockets='1' cores='2' threads='1'/>
|
|
<feature policy='disable' name='lahf_lm'/>
|
|
</cpu>
|
|
...</pre>
|
|
|
|
<pre>
|
|
<cpu mode='host-model'>
|
|
<model fallback='forbid'/>
|
|
<topology sockets='1' cores='2' threads='1'/>
|
|
</cpu>
|
|
...</pre>
|
|
|
|
<pre>
|
|
<cpu mode='host-passthrough'/>
|
|
<feature policy='disable' name='lahf_lm'/>
|
|
...</pre>
|
|
|
|
<p>
|
|
In case no restrictions need to be put on CPU model and its features, a
|
|
simpler <code>cpu</code> element can be used.
|
|
<span class="since">Since 0.7.6</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<cpu>
|
|
<topology sockets='1' cores='2' threads='1'/>
|
|
</cpu>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>cpu</code></dt>
|
|
<dd>The <code>cpu</code> element is the main container for describing
|
|
guest CPU requirements. Its <code>match</code> attribute specified how
|
|
strictly has the virtual CPU provided to the guest match these
|
|
requirements. <span class="since">Since 0.7.6</span> the
|
|
<code>match</code> attribute can be omitted if <code>topology</code>
|
|
is the only element within <code>cpu</code>. Possible values for the
|
|
<code>match</code> attribute are:
|
|
|
|
<dl>
|
|
<dt><code>minimum</code></dt>
|
|
<dd>The specified CPU model and features describes the minimum
|
|
requested CPU.</dd>
|
|
<dt><code>exact</code></dt>
|
|
<dd>The virtual CPU provided to the guest will exactly match the
|
|
specification</dd>
|
|
<dt><code>strict</code></dt>
|
|
<dd>The guest will not be created unless the host CPU does exactly
|
|
match the specification.</dd>
|
|
</dl>
|
|
|
|
<span class="since">Since 0.8.5</span> the <code>match</code>
|
|
attribute can be omitted and will default to <code>exact</code>.
|
|
|
|
<span class="since">Since 0.9.10</span>, an optional <code>mode</code>
|
|
attribute may be used to make it easier to configure a guest CPU to be
|
|
as close to host CPU as possible. Possible values for the
|
|
<code>mode</code> attribute are:
|
|
|
|
<dl>
|
|
<dt><code>custom</code></dt>
|
|
<dd>In this mode, the <code>cpu</code> element describes the CPU
|
|
that should be presented to the guest. This is the default when no
|
|
<code>mode</code> attribute is specified. This mode makes it so that
|
|
a persistent guest will see the same hardware no matter what host
|
|
the guest is booted on.</dd>
|
|
<dt><code>host-model</code></dt>
|
|
<dd>The <code>host-model</code> mode is essentially a shortcut to
|
|
copying host CPU definition from capabilities XML into domain XML.
|
|
Since the CPU definition is copied just before starting a domain,
|
|
exactly the same XML can be used on different hosts while still
|
|
providing the best guest CPU each host supports. The
|
|
<code>match</code> attribute can't be used in this mode. Specifying
|
|
CPU model is not supported either, but <code>model</code>'s
|
|
<code>fallback</code> attribute may still be used. Using the
|
|
<code>feature</code> element, specific flags may be enabled or
|
|
disabled specifically in addition to the host model. This may be
|
|
used to fine tune features that can be emulated.
|
|
<span class="since">(Since 1.1.1)</span>.
|
|
Libvirt does not model every aspect of each CPU so
|
|
the guest CPU will not match the host CPU exactly. On the other
|
|
hand, the ABI provided to the guest is reproducible. During
|
|
migration, complete CPU model definition is transferred to the
|
|
destination host so the migrated guest will see exactly the same CPU
|
|
model even if the destination host contains more capable CPUs for
|
|
the running instance of the guest; but shutting down and restarting
|
|
the guest may present different hardware to the guest according to
|
|
the capabilities of the new host. <strong>Beware</strong>, due to the
|
|
way libvirt detects host CPU and due to the fact libvirt does not
|
|
talk to QEMU/KVM when creating the CPU model, CPU configuration
|
|
created using <code>host-model</code> may not work as expected. The
|
|
guest CPU may differ from the configuration and it may also confuse
|
|
guest OS by using a combination of CPU features and other parameters
|
|
(such as CPUID level) that don't work. Until these issues are fixed,
|
|
it's a good idea to avoid using <code>host-model</code> and use
|
|
<code>custom</code> mode with just the CPU model from host
|
|
capabilities XML.
|
|
<span class="since">(Since 1.2.11)</span>. PowerISA allows
|
|
processors to run VMs in binary compatibility mode supporting an
|
|
older version of ISA. Libvirt on PowerPC architecture uses the
|
|
<code>host-model</code> to signify a guest mode CPU running in
|
|
binary compatibility mode. Example:
|
|
When a user needs a power7 VM to run in compatibility mode
|
|
on a Power8 host, this can be described in XML as follows :
|
|
<pre>
|
|
<cpu mode='host-model'>
|
|
<model>power7</model>
|
|
</cpu>
|
|
...</pre>
|
|
</dd>
|
|
<dt><code>host-passthrough</code></dt>
|
|
<dd>With this mode, the CPU visible to the guest should be exactly
|
|
the same as the host CPU even in the aspects that libvirt does not
|
|
understand. Though the downside of this mode is that the guest
|
|
environment cannot be reproduced on different hardware. Thus, if you
|
|
hit any bugs, you are on your own. Further details of that CPU can
|
|
be changed using <code>feature</code> elements.</dd>
|
|
</dl>
|
|
|
|
In both <code>host-model</code> and <code>host-passthrough</code>
|
|
mode, the real (approximate in <code>host-passthrough</code> mode) CPU
|
|
definition which would be used on current host can be determined by
|
|
specifying <code>VIR_DOMAIN_XML_UPDATE_CPU</code> flag when calling
|
|
<code>virDomainGetXMLDesc</code> API. When running a guest that might
|
|
be prone to operating system reactivation when presented with
|
|
different hardware, and which will be migrated between hosts with
|
|
different capabilities, you can use this output to rewrite XML to the
|
|
<code>custom</code> mode for more robust migration.
|
|
</dd>
|
|
|
|
<dt><code>model</code></dt>
|
|
<dd>The content of the <code>model</code> element specifies CPU model
|
|
requested by the guest. The list of available CPU models and their
|
|
definition can be found in <code>cpu_map.xml</code> file installed
|
|
in libvirt's data directory. If a hypervisor is not able to use the
|
|
exact CPU model, libvirt automatically falls back to a closest model
|
|
supported by the hypervisor while maintaining the list of CPU
|
|
features. <span class="since">Since 0.9.10</span>, an optional
|
|
<code>fallback</code> attribute can be used to forbid this behavior,
|
|
in which case an attempt to start a domain requesting an unsupported
|
|
CPU model will fail. Supported values for <code>fallback</code>
|
|
attribute are: <code>allow</code> (this is the default), and
|
|
<code>forbid</code>. The optional <code>vendor_id</code> attribute
|
|
(<span class="since">Since 0.10.0</span>) can be used to set the
|
|
vendor id seen by the guest. It must be exactly 12 characters long.
|
|
If not set the vendor id of the host is used. Typical possible
|
|
values are "AuthenticAMD" and "GenuineIntel".</dd>
|
|
|
|
<dt><code>vendor</code></dt>
|
|
<dd><span class="since">Since 0.8.3</span> the content of the
|
|
<code>vendor</code> element specifies CPU vendor requested by the
|
|
guest. If this element is missing, the guest can be run on a CPU
|
|
matching given features regardless on its vendor. The list of
|
|
supported vendors can be found in <code>cpu_map.xml</code>.</dd>
|
|
|
|
<dt><code>topology</code></dt>
|
|
<dd>The <code>topology</code> element specifies requested topology of
|
|
virtual CPU provided to the guest. Three non-zero values have to be
|
|
given for <code>sockets</code>, <code>cores</code>, and
|
|
<code>threads</code>: total number of CPU sockets, number of cores per
|
|
socket, and number of threads per core, respectively.</dd>
|
|
|
|
<dt><code>feature</code></dt>
|
|
<dd>The <code>cpu</code> element can contain zero or more
|
|
<code>elements</code> used to fine-tune features provided by the
|
|
selected CPU model. The list of known feature names can be found in
|
|
the same file as CPU models. The meaning of each <code>feature</code>
|
|
element depends on its <code>policy</code> attribute, which has to be
|
|
set to one of the following values:
|
|
|
|
<dl>
|
|
<dt><code>force</code></dt>
|
|
<dd>The virtual CPU will claim the feature is supported regardless
|
|
of it being supported by host CPU.</dd>
|
|
<dt><code>require</code></dt>
|
|
<dd>Guest creation will fail unless the feature is supported by host
|
|
CPU.</dd>
|
|
<dt><code>optional</code></dt>
|
|
<dd>The feature will be supported by virtual CPU if and only if it
|
|
is supported by host CPU.</dd>
|
|
<dt><code>disable</code></dt>
|
|
<dd>The feature will not be supported by virtual CPU.</dd>
|
|
<dt><code>forbid</code></dt>
|
|
<dd>Guest creation will fail if the feature is supported by host
|
|
CPU.</dd>
|
|
</dl>
|
|
|
|
<span class="since">Since 0.8.5</span> the <code>policy</code>
|
|
attribute can be omitted and will default to <code>require</code>.
|
|
</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
Guest NUMA topology can be specified using the <code>numa</code> element.
|
|
<span class="since">Since 0.9.8</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<cpu>
|
|
...
|
|
<numa>
|
|
<cell id='0' cpus='0-3' memory='512000' unit='KiB'/>
|
|
<cell id='1' cpus='4-7' memory='512000' unit='KiB' memAccess='shared'/>
|
|
</numa>
|
|
...
|
|
</cpu>
|
|
...</pre>
|
|
|
|
<p>
|
|
Each <code>cell</code> element specifies a NUMA cell or a NUMA node.
|
|
<code>cpus</code> specifies the CPU or range of CPUs that are
|
|
part of the node. <code>memory</code> specifies the node memory
|
|
in kibibytes (i.e. blocks of 1024 bytes).
|
|
<span class="since">Since 1.2.11</span> one can use an additional <a
|
|
href="#elementsMemoryAllocation"><code>unit</code></a> attribute to
|
|
define units in which <code>memory</code> is specified.
|
|
<span class="since">Since 1.2.7</span> all cells should
|
|
have <code>id</code> attribute in case referring to some cell is
|
|
necessary in the code, otherwise the cells are
|
|
assigned <code>id</code>s in the increasing order starting from
|
|
0. Mixing cells with and without the <code>id</code> attribute
|
|
is not recommended as it may result in unwanted behaviour.
|
|
|
|
<span class='since'>Since 1.2.9</span> the optional attribute
|
|
<code>memAccess</code> can control whether the memory is to be
|
|
mapped as "shared" or "private". This is valid only for
|
|
hugepages-backed memory.
|
|
</p>
|
|
|
|
<p>
|
|
This guest NUMA specification is currently available only for QEMU/KVM.
|
|
</p>
|
|
|
|
<h3><a name="elementsEvents">Events configuration</a></h3>
|
|
|
|
<p>
|
|
It is sometimes necessary to override the default actions taken
|
|
on various events. Not all hypervisors support all events and actions.
|
|
The actions may be taken as a result of calls to libvirt APIs
|
|
<a href="html/libvirt-libvirt-domain.html#virDomainReboot">
|
|
<code>virDomainReboot</code>
|
|
</a>,
|
|
<a href="html/libvirt-libvirt-domain.html#virDomainShutdown">
|
|
<code>virDomainShutdown</code>
|
|
</a>,
|
|
or
|
|
<a href="html/libvirt-libvirt-domain.html#virDomainShutdownFlags">
|
|
<code>virDomainShutdownFlags</code>
|
|
</a>.
|
|
Using <code>virsh reboot</code> or <code>virsh shutdown</code> would
|
|
also trigger the event.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<on_poweroff>destroy</on_poweroff>
|
|
<on_reboot>restart</on_reboot>
|
|
<on_crash>restart</on_crash>
|
|
<on_lockfailure>poweroff</on_lockfailure>
|
|
...</pre>
|
|
|
|
<p>
|
|
The following collections of elements allow the actions to be
|
|
specified when a guest OS triggers a lifecycle operation. A
|
|
common use case is to force a reboot to be treated as a poweroff
|
|
when doing the initial OS installation. This allows the VM to be
|
|
re-configured for the first post-install bootup.
|
|
</p>
|
|
<dl>
|
|
<dt><code>on_poweroff</code></dt>
|
|
<dd>The content of this element specifies the action to take when
|
|
the guest requests a poweroff.</dd>
|
|
<dt><code>on_reboot</code></dt>
|
|
<dd>The content of this element specifies the action to take when
|
|
the guest requests a reboot.</dd>
|
|
<dt><code>on_crash</code></dt>
|
|
<dd>The content of this element specifies the action to take when
|
|
the guest crashes.</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
Each of these states allow for the same four possible actions.
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>destroy</code></dt>
|
|
<dd>The domain will be terminated completely and all resources
|
|
released.</dd>
|
|
<dt><code>restart</code></dt>
|
|
<dd>The domain will be terminated and then restarted with
|
|
the same configuration.</dd>
|
|
<dt><code>preserve</code></dt>
|
|
<dd>The domain will be terminated and its resource preserved
|
|
to allow analysis.</dd>
|
|
<dt><code>rename-restart</code></dt>
|
|
<dd>The domain will be terminated and then restarted with
|
|
a new name.</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
QEMU/KVM supports the <code>on_poweroff</code> and <code>on_reboot</code>
|
|
events handling the <code>destroy</code> and <code>restart</code> actions.
|
|
The <code>preserve</code> action for an <code>on_reboot</code> event
|
|
is treated as a <code>destroy</code> and the <code>rename-restart</code>
|
|
action for an <code>on_poweroff</code> event is treated as a
|
|
<code>restart</code> event.
|
|
</p>
|
|
|
|
<p>
|
|
The <code>on_crash</code> event supports these additional
|
|
actions <span class="since">since 0.8.4</span>.
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>coredump-destroy</code></dt>
|
|
<dd>The crashed domain's core will be dumped, and then the
|
|
domain will be terminated completely and all resources
|
|
released</dd>
|
|
<dt><code>coredump-restart</code></dt>
|
|
<dd>The crashed domain's core will be dumped, and then the
|
|
domain will be restarted with the same configuration</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
The <code>on_lockfailure</code> element (<span class="since">since
|
|
1.0.0</span>) may be used to configure what action should be
|
|
taken when a lock manager loses resource locks. The following
|
|
actions are recognized by libvirt, although not all of them need
|
|
to be supported by individual lock managers. When no action is
|
|
specified, each lock manager will take its default action.
|
|
</p>
|
|
<dl>
|
|
<dt><code>poweroff</code></dt>
|
|
<dd>The domain will be forcefully powered off.</dd>
|
|
<dt><code>restart</code></dt>
|
|
<dd>The domain will be powered off and started up again to
|
|
reacquire its locks.</dd>
|
|
<dt><code>pause</code></dt>
|
|
<dd>The domain will be paused so that it can be manually resumed
|
|
when lock issues are solved.</dd>
|
|
<dt><code>ignore</code></dt>
|
|
<dd>Keep the domain running as if nothing happened.</dd>
|
|
</dl>
|
|
|
|
<h3><a name="elementsPowerManagement">Power Management</a></h3>
|
|
|
|
<p>
|
|
<span class="since">Since 0.10.2</span> it is possible to
|
|
forcibly enable or disable BIOS advertisements to the guest
|
|
OS. (NB: Only qemu driver support)
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<pm>
|
|
<suspend-to-disk enabled='no'/>
|
|
<suspend-to-mem enabled='yes'/>
|
|
</pm>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>pm</code></dt>
|
|
<dd>These elements enable ('yes') or disable ('no') BIOS support
|
|
for S3 (suspend-to-disk) and S4 (suspend-to-mem) ACPI sleep
|
|
states. If nothing is specified, then the hypervisor will be
|
|
left with its default value.</dd>
|
|
</dl>
|
|
|
|
<h3><a name="elementsFeatures">Hypervisor features</a></h3>
|
|
|
|
<p>
|
|
Hypervisors may allow certain CPU / machine features to be
|
|
toggled on/off.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<features>
|
|
<pae/>
|
|
<acpi/>
|
|
<apic/>
|
|
<hap/>
|
|
<privnet/>
|
|
<hyperv>
|
|
<relaxed state='on'/>
|
|
<vapic state='on'/>
|
|
<spinlocks state='on' retries='4096'/>
|
|
</hyperv>
|
|
<kvm>
|
|
<hidden state='on'/>
|
|
</kvm>
|
|
<pvspinlock/>
|
|
|
|
</features>
|
|
...</pre>
|
|
|
|
<p>
|
|
All features are listed within the <code>features</code>
|
|
element, omitting a togglable feature tag turns it off.
|
|
The available features can be found by asking
|
|
for the <a href="formatcaps.html">capabilities XML</a>,
|
|
but a common set for fully virtualized domains are:
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>pae</code></dt>
|
|
<dd>Physical address extension mode allows 32-bit guests
|
|
to address more than 4 GB of memory.</dd>
|
|
<dt><code>acpi</code></dt>
|
|
<dd>ACPI is useful for power management, for example, with
|
|
KVM guests it is required for graceful shutdown to work.
|
|
</dd>
|
|
<dt><code>apic</code></dt>
|
|
<dd>APIC allows the use of programmable IRQ
|
|
management. <span class="since">Since 0.10.2 (QEMU only)</span> there is
|
|
an optional attribute <code>eoi</code> with values <code>on</code>
|
|
and <code>off</code> which toggles the availability of EOI (End of
|
|
Interrupt) for the guest.
|
|
</dd>
|
|
<dt><code>hap</code></dt>
|
|
<dd>Enable use of Hardware Assisted Paging if available in
|
|
the hardware.
|
|
</dd>
|
|
<dt><code>viridian</code></dt>
|
|
<dd>Enable Viridian hypervisor extensions for paravirtualizing
|
|
guest operating systems
|
|
</dd>
|
|
<dt><code>privnet</code></dt>
|
|
<dd>Always create a private network namespace. This is
|
|
automatically set if any interface devices are defined.
|
|
This feature is only relevant for container based
|
|
virtualization drivers, such as LXC.
|
|
</dd>
|
|
<dt><code>hyperv</code></dt>
|
|
<dd>Enable various features improving behavior of guests
|
|
running Microsoft Windows.
|
|
<table class="top_table">
|
|
<tr>
|
|
<th>Feature</th>
|
|
<th>Description</th>
|
|
<th>Value</th>
|
|
<th>Since</th>
|
|
</tr>
|
|
<tr>
|
|
<td>relaxed</td>
|
|
<td>Relax constraints on timers</td>
|
|
<td> on, off</td>
|
|
<td><span class="since">1.0.0 (QEMU only)</span></td>
|
|
</tr>
|
|
<tr>
|
|
<td>vapic</td>
|
|
<td>Enable virtual APIC</td>
|
|
<td>on, off</td>
|
|
<td><span class="since">1.1.0 (QEMU only)</span></td>
|
|
</tr>
|
|
<tr>
|
|
<td>spinlocks</td>
|
|
<td>Enable spinlock support</td>
|
|
<td>on, off; retries - at least 4095</td>
|
|
<td><span class="since">1.1.0 (QEMU only)</span></td>
|
|
</tr>
|
|
</table>
|
|
</dd>
|
|
<dt><code>pvspinlock</code></dt>
|
|
<dd>Notify the guest that the host supports paravirtual spinlocks
|
|
for example by exposing the pvticketlocks mechanism. This feature
|
|
can be explicitly disabled by using <code>state='off'</code>
|
|
attribute.
|
|
</dd>
|
|
<dt><code>kvm</code></dt>
|
|
<dd>Various features to change the behavior of the KVM hypervisor.
|
|
<table class="top_table">
|
|
<tr>
|
|
<th>Feature</th>
|
|
<th>Description</th>
|
|
<th>Value</th>
|
|
<th>Since</th>
|
|
</tr>
|
|
<tr>
|
|
<td>hidden</td>
|
|
<td>Hide the KVM hypervisor from standard MSR based discovery</td>
|
|
<td>on, off</td>
|
|
<td><span class="since">2.1.0 (QEMU only)</span></td>
|
|
</tr>
|
|
</table>
|
|
</dd>
|
|
<dt><code>pmu</code></dt>
|
|
<dd>Depending on the <code>state</code> attribute (values <code>on</code>,
|
|
<code>off</code>, default <code>on</code>) enable or disable the
|
|
performance monitoring unit for the guest.
|
|
<span class="since">Since 1.2.12</span>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h3><a name="elementsTime">Time keeping</a></h3>
|
|
|
|
<p>
|
|
The guest clock is typically initialized from the host clock.
|
|
Most operating systems expect the hardware clock to be kept
|
|
in UTC, and this is the default. Windows, however, expects
|
|
it to be in so called 'localtime'.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<clock offset='localtime'>
|
|
<timer name='rtc' tickpolicy='catchup' track='guest'>
|
|
<catchup threshold='123' slew='120' limit='10000'/>
|
|
</timer>
|
|
<timer name='pit' tickpolicy='delay'/>
|
|
</clock>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>clock</code></dt>
|
|
<dd>
|
|
<p>The <code>offset</code> attribute takes four possible
|
|
values, allowing fine grained control over how the guest
|
|
clock is synchronized to the host. NB, not all hypervisors
|
|
support all modes.</p>
|
|
<dl>
|
|
<dt><code>utc</code></dt>
|
|
<dd>
|
|
The guest clock will always be synchronized to UTC when
|
|
booted.
|
|
<span class="since">Since 0.9.11</span> 'utc' mode can be converted
|
|
to 'variable' mode, which can be controlled by using the
|
|
<code>adjustment</code> attribute. If the value is 'reset', the
|
|
conversion is never done (not all hypervisors can
|
|
synchronize to UTC on each boot; use of 'reset' will cause
|
|
an error on those hypervisors). A numeric value
|
|
forces the conversion to 'variable' mode using the value as the
|
|
initial adjustment. The default <code>adjustment</code> is
|
|
hypervisor specific.
|
|
</dd>
|
|
<dt><code>localtime</code></dt>
|
|
<dd>
|
|
The guest clock will be synchronized to the host's configured
|
|
timezone when booted, if any.
|
|
<span class="since">Since 0.9.11,</span> the <code>adjustment</code>
|
|
attribute behaves the same as in 'utc' mode.
|
|
</dd>
|
|
<dt><code>timezone</code></dt>
|
|
<dd>
|
|
The guest clock will be synchronized to the requested timezone
|
|
using the <code>timezone</code> attribute.
|
|
<span class="since">Since 0.7.7</span>
|
|
</dd>
|
|
<dt><code>variable</code></dt>
|
|
<dd>
|
|
The guest clock will have an arbitrary offset applied
|
|
relative to UTC or localtime, depending on the <code>basis</code>
|
|
attribute. The delta relative to UTC (or localtime) is specified
|
|
in seconds, using the <code>adjustment</code> attribute.
|
|
The guest is free to adjust the RTC over time and expect
|
|
that it will be honored at next reboot. This is in
|
|
contrast to 'utc' and 'localtime' mode (with the optional
|
|
attribute adjustment='reset'), where the RTC adjustments are
|
|
lost at each reboot. <span class="since">Since 0.7.7</span>
|
|
<span class="since">Since 0.9.11</span> the <code>basis</code>
|
|
attribute can be either 'utc' (default) or 'localtime'.
|
|
</dd>
|
|
</dl>
|
|
<p>
|
|
A <code>clock</code> may have zero or more
|
|
<code>timer</code> sub-elements. <span class="since">Since
|
|
0.8.0</span>
|
|
</p>
|
|
</dd>
|
|
<dt><code>timer</code></dt>
|
|
<dd>
|
|
<p>
|
|
Each timer element requires a <code>name</code> attribute,
|
|
and has other optional attributes that depend on
|
|
the <code>name</code> specified. Various hypervisors
|
|
support different combinations of attributes.
|
|
</p>
|
|
<dl>
|
|
<dt><code>name</code></dt>
|
|
<dd>
|
|
The <code>name</code> attribute selects which timer is
|
|
being modified, and can be one of
|
|
"platform" (currently unsupported),
|
|
"hpet" (libxl, xen, qemu), "kvmclock" (qemu),
|
|
"pit" (qemu), "rtc" (qemu), "tsc" (libxl) or "hypervclock"
|
|
(qemu - <span class="since">since 1.2.2</span>).
|
|
|
|
The <code>hypervclock</code> timer adds support for the
|
|
reference time counter and the reference page for iTSC
|
|
feature for guests running the Microsoft Windows
|
|
operating system.
|
|
</dd>
|
|
<dt><code>track</code></dt>
|
|
<dd>
|
|
The <code>track</code> attribute specifies what the timer
|
|
tracks, and can be "boot", "guest", or "wall".
|
|
Only valid for <code>name="rtc"</code>
|
|
or <code>name="platform"</code>.
|
|
</dd>
|
|
<dt><code>tickpolicy</code></dt>
|
|
<dd>
|
|
<p>
|
|
The <code>tickpolicy</code> attribute determines what
|
|
happens when QEMU misses a deadline for injecting a
|
|
tick to the guest:
|
|
</p>
|
|
<dl>
|
|
<dt><code>delay</code></dt>
|
|
<dd>Continue to deliver ticks at the normal rate.
|
|
The guest time will be delayed due to the late
|
|
tick</dd>
|
|
<dt><code>catchup</code></dt>
|
|
<dd>Deliver ticks at a higher rate to catch up
|
|
with the missed tick. The guest time should
|
|
not be delayed once catchup is complete.</dd>
|
|
<dt><code>merge</code></dt>
|
|
<dd>Merge the missed tick(s) into one tick and
|
|
inject. The guest time may be delayed, depending
|
|
on how the OS reacts to the merging of ticks</dd>
|
|
<dt><code>discard</code></dt>
|
|
<dd>Throw away the missed tick(s) and continue
|
|
with future injection normally. The guest time
|
|
may be delayed, unless the OS has explicit
|
|
handling of lost ticks</dd>
|
|
</dl>
|
|
<p>If the policy is "catchup", there can be further details in
|
|
the <code>catchup</code> sub-element.</p>
|
|
<dl>
|
|
<dt><code>catchup</code></dt>
|
|
<dd>
|
|
The <code>catchup</code> element has three optional
|
|
attributes, each a positive integer. The attributes
|
|
are <code>threshold</code>, <code>slew</code>,
|
|
and <code>limit</code>.
|
|
</dd>
|
|
</dl>
|
|
<p>
|
|
Note that hypervisors are not required to support all policies across all time sources
|
|
</p>
|
|
</dd>
|
|
<dt><code>frequency</code></dt>
|
|
<dd>
|
|
The <code>frequency</code> attribute is an unsigned
|
|
integer specifying the frequency at
|
|
which <code>name="tsc"</code> runs.
|
|
</dd>
|
|
<dt><code>mode</code></dt>
|
|
<dd>
|
|
The <code>mode</code> attribute controls how
|
|
the <code>name="tsc"</code> timer is managed, and can be
|
|
"auto", "native", "emulate", "paravirt", or "smpsafe".
|
|
Other timers are always emulated.
|
|
</dd>
|
|
<dt><code>present</code></dt>
|
|
<dd>
|
|
The <code>present</code> attribute can be "yes" or "no" to
|
|
specify whether a particular timer is available to the guest.
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h3><a name="elementsDevices">Devices</a></h3>
|
|
|
|
<p>
|
|
The final set of XML elements are all used to describe devices
|
|
provided to the guest domain. All devices occur as children
|
|
of the main <code>devices</code> element.
|
|
<span class="since">Since 0.1.3</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<emulator>/usr/lib/xen/bin/qemu-dm</emulator>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>emulator</code></dt>
|
|
<dd>
|
|
The contents of the <code>emulator</code> element specify
|
|
the fully qualified path to the device model emulator binary.
|
|
The <a href="formatcaps.html">capabilities XML</a> specifies
|
|
the recommended default emulator to use for each particular
|
|
domain type / architecture combination.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsDisks">Hard drives, floppy disks, CDROMs</a></h4>
|
|
|
|
<p>
|
|
Any device that looks like a disk, be it a floppy, harddisk,
|
|
cdrom, or paravirtualized driver is specified via the <code>disk</code>
|
|
element.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<disk type='file' snapshot='external'>
|
|
<driver name="tap" type="aio" cache="default"/>
|
|
<source file='/var/lib/xen/images/fv0' startupPolicy='optional'>
|
|
<seclabel relabel='no'/>
|
|
</source>
|
|
<target dev='hda' bus='ide'/>
|
|
<iotune>
|
|
<total_bytes_sec>10000000</total_bytes_sec>
|
|
<read_iops_sec>400000</read_iops_sec>
|
|
<write_iops_sec>100000</write_iops_sec>
|
|
</iotune>
|
|
<boot order='2'/>
|
|
<encryption type='...'>
|
|
...
|
|
</encryption>
|
|
<shareable/>
|
|
<serial>
|
|
...
|
|
</serial>
|
|
</disk>
|
|
...
|
|
<disk type='network'>
|
|
<driver name="qemu" type="raw" io="threads" ioeventfd="on" event_idx="off"/>
|
|
<source protocol="sheepdog" name="image_name">
|
|
<host name="hostname" port="7000"/>
|
|
</source>
|
|
<target dev="hdb" bus="ide"/>
|
|
<boot order='1'/>
|
|
<transient/>
|
|
<address type='drive' controller='0' bus='1' unit='0'/>
|
|
</disk>
|
|
<disk type='network'>
|
|
<driver name="qemu" type="raw"/>
|
|
<source protocol="rbd" name="image_name2">
|
|
<host name="hostname" port="7000"/>
|
|
<snapshot name="snapname"/>
|
|
<config file="/path/to/file"/>
|
|
</source>
|
|
<target dev="hdc" bus="ide"/>
|
|
<auth username='myuser'>
|
|
<secret type='ceph' usage='mypassid'/>
|
|
</auth>
|
|
</disk>
|
|
<disk type='block' device='cdrom'>
|
|
<driver name='qemu' type='raw'/>
|
|
<target dev='hdd' bus='ide' tray='open'/>
|
|
<readonly/>
|
|
</disk>
|
|
<disk type='network' device='cdrom'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source protocol="http" name="url_path">
|
|
<host name="hostname" port="80"/>
|
|
</source>
|
|
<target dev='hde' bus='ide' tray='open'/>
|
|
<readonly/>
|
|
</disk>
|
|
<disk type='network' device='cdrom'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source protocol="https" name="url_path">
|
|
<host name="hostname" port="443"/>
|
|
</source>
|
|
<target dev='hdf' bus='ide' tray='open'/>
|
|
<readonly/>
|
|
</disk>
|
|
<disk type='network' device='cdrom'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source protocol="ftp" name="url_path">
|
|
<host name="hostname" port="21"/>
|
|
</source>
|
|
<target dev='hdg' bus='ide' tray='open'/>
|
|
<readonly/>
|
|
</disk>
|
|
<disk type='network' device='cdrom'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source protocol="ftps" name="url_path">
|
|
<host name="hostname" port="990"/>
|
|
</source>
|
|
<target dev='hdh' bus='ide' tray='open'/>
|
|
<readonly/>
|
|
</disk>
|
|
<disk type='network' device='cdrom'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source protocol="tftp" name="url_path">
|
|
<host name="hostname" port="69"/>
|
|
</source>
|
|
<target dev='hdi' bus='ide' tray='open'/>
|
|
<readonly/>
|
|
</disk>
|
|
<disk type='block' device='lun'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source dev='/dev/sda'/>
|
|
<target dev='sda' bus='scsi'/>
|
|
<address type='drive' controller='0' bus='0' target='3' unit='0'/>
|
|
</disk>
|
|
<disk type='block' device='disk'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source dev='/dev/sda'/>
|
|
<geometry cyls='16383' heads='16' secs='63' trans='lba'/>
|
|
<blockio logical_block_size='512' physical_block_size='4096'/>
|
|
<target dev='hdj' bus='ide'/>
|
|
</disk>
|
|
<disk type='volume' device='disk'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source pool='blk-pool0' volume='blk-pool0-vol0'/>
|
|
<target dev='hdk' bus='ide'/>
|
|
</disk>
|
|
<disk type='network' device='disk'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source protocol='iscsi' name='iqn.2013-07.com.example:iscsi-nopool/2'>
|
|
<host name='example.com' port='3260'/>
|
|
</source>
|
|
<auth username='myuser'>
|
|
<secret type='iscsi' usage='libvirtiscsi'/>
|
|
</auth>
|
|
<target dev='vda' bus='virtio'/>
|
|
</disk>
|
|
<disk type='network' device='lun'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source protocol='iscsi' name='iqn.2013-07.com.example:iscsi-nopool/1'>
|
|
<host name='example.com' port='3260'/>
|
|
</source>
|
|
<auth username='myuser'>
|
|
<secret type='iscsi' usage='libvirtiscsi'/>
|
|
</auth>
|
|
<target dev='sdb' bus='scsi'/>
|
|
</disk>
|
|
<disk type='volume' device='disk'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source pool='iscsi-pool' volume='unit:0:0:1' mode='host'/>
|
|
<auth username='myuser'>
|
|
<secret type='iscsi' usage='libvirtiscsi'/>
|
|
</auth>
|
|
<target dev='vdb' bus='virtio'/>
|
|
</disk>
|
|
<disk type='volume' device='disk'>
|
|
<driver name='qemu' type='raw'/>
|
|
<source pool='iscsi-pool' volume='unit:0:0:2' mode='direct'/>
|
|
<auth username='myuser'>
|
|
<secret type='iscsi' usage='libvirtiscsi'/>
|
|
</auth>
|
|
<target dev='vdc' bus='virtio'/>
|
|
</disk>
|
|
<disk type='file' device='disk'>
|
|
<driver name='qemu' type='qcow2'/>
|
|
<source file='/var/lib/libvirt/images/domain.qcow'/>
|
|
<backingStore type='file'>
|
|
<format type='qcow2'/>
|
|
<source file='/var/lib/libvirt/images/snapshot.qcow'/>
|
|
<backingStore type='block'>
|
|
<format type='raw'/>
|
|
<source dev='/dev/mapper/base'/>
|
|
<backingStore/>
|
|
</backingStore>
|
|
</backingStore>
|
|
<target dev='vdd' bus='virtio'/>
|
|
</disk>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>disk</code></dt>
|
|
<dd>The <code>disk</code> element is the main container for describing
|
|
disks (<span class="since">since 0.0.3</span>).
|
|
<dl>
|
|
<dt><code>type</code> attribute
|
|
<span class="since">since 0.0.3</span></dt>
|
|
<dd>
|
|
Valid values are "file", "block",
|
|
"dir" (<span class="since">since 0.7.5</span>),
|
|
"network" (<span class="since">since 0.8.7</span>), or
|
|
"volume" (<span class="since">since 1.0.5</span>)
|
|
and refer to the underlying source for the disk.
|
|
</dd>
|
|
<dt><code>device</code> attribute
|
|
<span class="since">since 0.1.4</span></dt>
|
|
<dd>
|
|
Indicates how the disk is to be exposed to the guest OS. Possible
|
|
values for this attribute are "floppy", "disk", "cdrom", and "lun",
|
|
defaulting to "disk".
|
|
<p>
|
|
Using "lun" (<span class="since">since 0.9.10</span>) is only
|
|
valid when type is "block" or "network" using the iSCSI protocol,
|
|
and behaves identically to "disk",
|
|
except that generic SCSI commands from the guest are accepted
|
|
and passed through to the physical device. Also note that
|
|
device='lun' will only be recognized for actual raw devices,
|
|
but never for individual partitions or LVM partitions (in those
|
|
cases, the kernel will reject the generic SCSI commands, making
|
|
it identical to device='disk').
|
|
</p>
|
|
</dd>
|
|
<dt><code>rawio</code> attribute
|
|
<span class="since">since 0.9.10</span></dt>
|
|
<dd>
|
|
Indicates whether the disk needs rawio capability. Valid
|
|
settings are "yes" or "no" (default is "no"). If any one disk
|
|
in a domain has rawio='yes', rawio capability will be enabled
|
|
for all disks in the domain (because, in the case of QEMU, this
|
|
capability can only be set on a per-process basis). This attribute
|
|
is only valid when device is "lun". NB, <code>rawio</code> intends
|
|
to confine the capability per-device, however, current QEMU
|
|
implementation gives the domain process broader capability
|
|
than that (per-process basis, affects all the domain disks).
|
|
To confine the capability as much as possible for QEMU driver
|
|
as this stage, <code>sgio</code> is recommended, it's more
|
|
secure than <code>rawio</code>.
|
|
</dd>
|
|
<dt><code>sgio</code> attribute
|
|
<span class="since">since 1.0.2</span></dt>
|
|
<dd>
|
|
Indicates whether the kernel will filter unprivileged
|
|
SG_IO commands for the disk, valid settings are "filtered" or
|
|
"unfiltered". Defaults to "filtered". Similar to <code>rawio</code>,
|
|
<code>sgio</code> is only valid for device 'lun'.
|
|
</dd>
|
|
<dt><code>snapshot</code> attribute
|
|
<span class="since">since 0.9.5</span></dt>
|
|
<dd>
|
|
Indicates the default behavior of the disk during disk snapshots:
|
|
"internal" requires a file format such as qcow2 that can store
|
|
both the snapshot and the data changes since the snapshot;
|
|
"external" will separate the snapshot from the live data; and
|
|
"no" means the disk will not participate in snapshots. Read-only
|
|
disks default to "no", while the default for other disks depends
|
|
on the hypervisor's capabilities. Some hypervisors allow a
|
|
per-snapshot choice as well, during
|
|
<a href="formatsnapshot.html">domain snapshot creation</a>.
|
|
Not all snapshot modes are supported; for example,
|
|
<code>snapshot='yes'</code> with a transient disk generally
|
|
does not make sense.
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
<dt><code>source</code></dt>
|
|
<dd>Representation of the disk <code>source</code> depends on the
|
|
disk <code>type</code> attribute value as follows:
|
|
<dl>
|
|
<dt><code>type='file'</code>
|
|
<span class="since">since 0.0.3</span></dt>
|
|
<dd>
|
|
The <code>file</code> attribute specifies the fully-qualified
|
|
path to the file holding the disk.
|
|
</dd>
|
|
<dt><code>type='block'</code>
|
|
<span class="since">since 0.0.3</span></dt>
|
|
<dd>
|
|
The <code>dev</code> attribute specifies the path to the
|
|
host device to serve as the disk.
|
|
</dd>
|
|
<dt><code>type='dir'</code>
|
|
<span class="since">since 0.7.5</span></dt>
|
|
<dd>
|
|
The <code>dir</code> attribute specifies the fully-qualified path
|
|
to the directory to use as the disk.
|
|
</dd>
|
|
<dt><code>type='network'</code>
|
|
<span class="since">since 0.8.7</span></dt>
|
|
<dd>
|
|
The <code>protocol</code> attribute specifies the protocol to
|
|
access to the requested image. Possible values are "nbd",
|
|
"iscsi", "rbd", "sheepdog" or "gluster". If the
|
|
<code>protocol</code> attribute is "rbd", "sheepdog" or
|
|
"gluster", an additional attribute <code>name</code> is
|
|
mandatory to specify which volume/image will be used. For "nbd",
|
|
the <code>name</code> attribute is optional. For "iscsi"
|
|
(<span class="since">since 1.0.4</span>), the <code>name</code>
|
|
attribute may include a logical unit number, separated from the
|
|
target's name by a slash (e.g.,
|
|
<code>iqn.2013-07.com.example:iscsi-pool/1</code>). If not
|
|
specified, the default LUN is zero.
|
|
</dd>
|
|
<dt><code>type='volume'</code>
|
|
<span class="since">since 1.0.5</span></dt>
|
|
<dd>
|
|
The underlying disk source is represented by attributes
|
|
<code>pool</code> and <code>volume</code>. Attribute
|
|
<code>pool</code> specifies the name of the
|
|
<a href="formatstorage.html">storage pool</a> (managed
|
|
by libvirt) where the disk source resides. Attribute
|
|
<code>volume</code> specifies the name of storage volume (managed
|
|
by libvirt) used as the disk source. The value for the
|
|
<code>volume</code> attribute will be the output from the "Name"
|
|
column of a <code>virsh vol-list [pool-name]</code> command.
|
|
<p>
|
|
Use the attribute <code>mode</code>
|
|
(<span class="since">since 1.1.1</span>) to indicate how to
|
|
represent the LUN as the disk source. Valid values are
|
|
"direct" and "host". If <code>mode</code> is not specified,
|
|
the default is to use "host".
|
|
|
|
Using "direct" as the <code>mode</code> value indicates to use
|
|
the <a href="formatstorage.html">storage pool's</a>
|
|
<code>source</code> element <code>host</code> attribute as
|
|
the disk source to generate the libiscsi URI (e.g.
|
|
'file=iscsi://example.com:3260/iqn.2013-07.com.example:iscsi-pool/1').
|
|
|
|
Using "host" as the <code>mode</code> value indicates to use the
|
|
LUN's path as it shows up on host (e.g.
|
|
'file=/dev/disk/by-path/ip-example.com:3260-iscsi-iqn.2013-07.com.example:iscsi-pool-lun-1').
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
With "file", "block", and "volume", one or more optional
|
|
sub-elements <code>seclabel</code>, <a href="#seclabel">described
|
|
below</a> (and <span class="since">since 0.9.9</span>), can be
|
|
used to override the domain security labeling policy for just
|
|
that source file. (NB, for "volume" type disk, <code>seclabel</code>
|
|
is only valid when the specified storage volume is of 'file' or
|
|
'block' type).
|
|
<p>
|
|
The <code>source</code> element may contain the following sub elements:
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>host</code></dt>
|
|
<dd>
|
|
<p>
|
|
When the disk <code>type</code> is "network", the <code>source</code>
|
|
may have zero or more <code>host</code> sub-elements used to
|
|
specify the hosts to connect.
|
|
|
|
The <code>host</code> element supports 4 attributes, viz. "name",
|
|
"port", "transport" and "socket", which specify the hostname,
|
|
the port number, transport type and path to socket, respectively.
|
|
The meaning of this element and the number of the elements depend
|
|
on the protocol attribute.
|
|
</p>
|
|
<table class="top_table">
|
|
<tr>
|
|
<th> Protocol </th>
|
|
<th> Meaning </th>
|
|
<th> Number of hosts </th>
|
|
<th> Default port </th>
|
|
</tr>
|
|
<tr>
|
|
<td> nbd </td>
|
|
<td> a server running nbd-server </td>
|
|
<td> only one </td>
|
|
<td> 10809 </td>
|
|
</tr>
|
|
<tr>
|
|
<td> iscsi </td>
|
|
<td> an iSCSI server </td>
|
|
<td> only one </td>
|
|
<td> 3260 </td>
|
|
</tr>
|
|
<tr>
|
|
<td> rbd </td>
|
|
<td> monitor servers of RBD </td>
|
|
<td> one or more </td>
|
|
<td> 6789 </td>
|
|
</tr>
|
|
<tr>
|
|
<td> sheepdog </td>
|
|
<td> one of the sheepdog servers (default is localhost:7000) </td>
|
|
<td> zero or one </td>
|
|
<td> 7000 </td>
|
|
</tr>
|
|
<tr>
|
|
<td> gluster </td>
|
|
<td> a server running glusterd daemon </td>
|
|
<td> only one </td>
|
|
<td> 24007 </td>
|
|
</tr>
|
|
</table>
|
|
<p>
|
|
gluster supports "tcp", "rdma", "unix" as valid values for the
|
|
transport attribute. nbd supports "tcp" and "unix". Others only
|
|
support "tcp". If nothing is specified, "tcp" is assumed. If the
|
|
transport is "unix", the socket attribute specifies the path to an
|
|
AF_UNIX socket.
|
|
</p>
|
|
</dd>
|
|
<dt><code>snapshot</code></dt>
|
|
<dd>
|
|
The <code>name</code> attribute of <code>snapshot</code> element can
|
|
optionally specify an internal snapshot name to be used as the
|
|
source for storage protocols.
|
|
Supported for 'rbd' <span class="since">since 1.2.11 (QEMU only).</span>
|
|
</dd>
|
|
<dt><code>config</code></dt>
|
|
<dd>
|
|
The <code>file</code> attribute for the <code>config</code> element
|
|
provides a fully qualified path to a configuration file to be
|
|
provided as a parameter to the client of a networked storage
|
|
protocol. Supported for 'rbd' <span class="since">since 1.2.11
|
|
(QEMU only).</span>
|
|
</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
For a "file" or "volume" disk type which represents a cdrom or floppy
|
|
(the <code>device</code> attribute), it is possible to define
|
|
policy what to do with the disk if the source file is not accessible.
|
|
(NB, <code>startupPolicy</code> is not valid for "volume" disk unless
|
|
the specified storage volume is of "file" type). This is done by the
|
|
<code>startupPolicy</code> attribute
|
|
(<span class="since">since 0.9.7</span>),
|
|
accepting these values:
|
|
</p>
|
|
<table class="top_table">
|
|
<tr>
|
|
<td> mandatory </td>
|
|
<td> fail if missing for any reason (the default) </td>
|
|
</tr>
|
|
<tr>
|
|
<td> requisite </td>
|
|
<td> fail if missing on boot up,
|
|
drop if missing on migrate/restore/revert </td>
|
|
</tr>
|
|
<tr>
|
|
<td> optional </td>
|
|
<td> drop if missing at any start attempt </td>
|
|
</tr>
|
|
</table>
|
|
<p>
|
|
<span class="since">Since 1.1.2</span> the <code>startupPolicy</code>
|
|
is extended to support hard disks besides cdrom and floppy. On guest
|
|
cold bootup, if a certain disk is not accessible or its disk chain is
|
|
broken, with startupPolicy 'optional' the guest will drop this disk.
|
|
This feature doesn't support migration currently.
|
|
</p>
|
|
</dd>
|
|
<dt><code>backingStore</code></dt>
|
|
<dd>
|
|
This element describes the backing store used by the disk specified by
|
|
sibling <code>source</code> element. It is currently ignored on input
|
|
and only used for output to describe the detected backing chains.
|
|
<span class="since">Since 1.2.4</span>. An empty
|
|
<code>backingStore</code> element means the sibling source is
|
|
self-contained and is not based on any backing store. The following
|
|
attributes and sub-elements are supported in
|
|
<code>backingStore</code>:
|
|
<dl>
|
|
<dt><code>type</code> attribute</dt>
|
|
<dd>
|
|
The <code>type</code> attribute represents the type of disk used
|
|
by the backing store, see disk type attribute above for more
|
|
details and possible values.
|
|
</dd>
|
|
<dt><code>index</code> attribute</dt>
|
|
<dd>
|
|
This attribute is only valid in output (and ignored on input) and
|
|
it can be used to refer to a specific part of the disk chain when
|
|
doing block operations (such as via the
|
|
<code>virDomainBlockRebase</code> API). For example,
|
|
<code>vda[2]</code> refers to the backing store with
|
|
<code>index='2'</code> of the disk with <code>vda</code> target.
|
|
</dd>
|
|
<dt><code>format</code> sub-element</dt>
|
|
<dd>
|
|
The <code>format</code> element contains <code>type</code>
|
|
attribute which specifies the internal format of the backing
|
|
store, such as <code>raw</code> or <code>qcow2</code>.
|
|
</dd>
|
|
<dt><code>source</code> sub-element</dt>
|
|
<dd>
|
|
This element has the same structure as the <code>source</code>
|
|
element in <code>disk</code>. It specifies which file, device,
|
|
or network location contains the data of the described backing
|
|
store.
|
|
</dd>
|
|
<dt><code>backingStore</code> sub-element</dt>
|
|
<dd>
|
|
If the backing store is not self-contained, the next element
|
|
in the chain is described by nested <code>backingStore</code>
|
|
element.
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
<dt><code>mirror</code></dt>
|
|
<dd>
|
|
This element is present if the hypervisor has started a
|
|
long-running block job operation, where the mirror location in
|
|
the <code>source</code> sub-element will eventually have the
|
|
same contents as the source, and with the file format in the
|
|
sub-element <code>format</code> (which might differ from the
|
|
format of the source). The details of the <code>source</code>
|
|
sub-element are determined by the <code>type</code> attribute
|
|
of the mirror, similar to what is done for the
|
|
overall <code>disk</code> device element. The <code>job</code>
|
|
attribute mentions which API started the operation ("copy" for
|
|
the <code>virDomainBlockRebase</code> API, or "active-commit"
|
|
for the <code>virDomainBlockCommit</code>
|
|
API), <span class="since">since 1.2.7</span>. The
|
|
attribute <code>ready</code>, if present, tracks progress of
|
|
the job: <code>yes</code> if the disk is known to be ready to
|
|
pivot, or, <span class="since">since
|
|
1.2.7</span>, <code>abort</code> or <code>pivot</code> if the
|
|
job is in the process of completing. If <code>ready</code> is
|
|
not present, the disk is probably still
|
|
copying. For now, this element only valid in output; it is
|
|
ignored on input. The <code>source</code> sub-element exists
|
|
for all two-phase jobs <span class="since">since 1.2.6</span>.
|
|
Older libvirt supported only block copy to a
|
|
file, <span class="since">since 0.9.12</span>; for
|
|
compatibility with older clients, such jobs include redundant
|
|
information in the attributes <code>file</code>
|
|
and <code>format</code> in the <code>mirror</code> element.
|
|
</dd>
|
|
<dt><code>target</code></dt>
|
|
<dd>The <code>target</code> element controls the bus / device
|
|
under which the disk is exposed to the guest
|
|
OS. The <code>dev</code> attribute indicates the "logical"
|
|
device name. The actual device name specified is not
|
|
guaranteed to map to the device name in the guest OS. Treat it
|
|
as a device ordering hint. The optional <code>bus</code>
|
|
attribute specifies the type of disk device to emulate;
|
|
possible values are driver specific, with typical values being
|
|
"ide", "scsi", "virtio", "xen", "usb", "sata", or
|
|
"sd" <span class="since">"sd" since 1.1.2</span>. If omitted, the bus
|
|
type is inferred from the style of the device name (e.g. a device named
|
|
'sda' will typically be exported using a SCSI bus). The optional
|
|
attribute <code>tray</code> indicates the tray status of the
|
|
removable disks (i.e. CDROM or Floppy disk), the value can be either
|
|
"open" or "closed", defaults to "closed". NB, the value of
|
|
<code>tray</code> could be updated while the domain is running.
|
|
The optional attribute <code>removable</code> sets the
|
|
removable flag for USB disks, and its value can be either "on"
|
|
or "off", defaulting to "off". <span class="since">Since
|
|
0.0.3; <code>bus</code> attribute since 0.4.3;
|
|
<code>tray</code> attribute since 0.9.11; "usb" attribute value since
|
|
after 0.4.4; "sata" attribute value since 0.9.7; "removable" attribute
|
|
value since 1.1.3</span>
|
|
</dd>
|
|
<dt><code>iotune</code></dt>
|
|
<dd>The optional <code>iotune</code> element provides the
|
|
ability to provide additional per-device I/O tuning, with
|
|
values that can vary for each device (contrast this to
|
|
the <a href="#elementsBlockTuning"><code><blkiotune></code></a>
|
|
element, which applies globally to the domain). Currently,
|
|
the only tuning available is Block I/O throttling for qemu.
|
|
This element has optional sub-elements; any sub-element not
|
|
specified or given with a value of 0 implies no
|
|
limit. <span class="since">Since 0.9.8</span>
|
|
<dl>
|
|
<dt><code>total_bytes_sec</code></dt>
|
|
<dd>The optional <code>total_bytes_sec</code> element is the
|
|
total throughput limit in bytes per second. This cannot
|
|
appear with <code>read_bytes_sec</code>
|
|
or <code>write_bytes_sec</code>.</dd>
|
|
<dt><code>read_bytes_sec</code></dt>
|
|
<dd>The optional <code>read_bytes_sec</code> element is the
|
|
read throughput limit in bytes per second.</dd>
|
|
<dt><code>write_bytes_sec</code></dt>
|
|
<dd>The optional <code>write_bytes_sec</code> element is the
|
|
write throughput limit in bytes per second.</dd>
|
|
<dt><code>total_iops_sec</code></dt>
|
|
<dd>The optional <code>total_iops_sec</code> element is the
|
|
total I/O operations per second. This cannot
|
|
appear with <code>read_iops_sec</code>
|
|
or <code>write_iops_sec</code>.</dd>
|
|
<dt><code>read_iops_sec</code></dt>
|
|
<dd>The optional <code>read_iops_sec</code> element is the
|
|
read I/O operations per second.</dd>
|
|
<dt><code>write_iops_sec</code></dt>
|
|
<dd>The optional <code>write_iops_sec</code> element is the
|
|
write I/O operations per second.</dd>
|
|
<dt><code>total_bytes_sec_max</code></dt>
|
|
<dd>The optional <code>total_bytes_sec_max</code> element is the
|
|
maximum total throughput limit in bytes per second. This cannot
|
|
appear with <code>read_bytes_sec_max</code>
|
|
or <code>write_bytes_sec_max</code>.</dd>
|
|
<dt><code>read_bytes_sec_max</code></dt>
|
|
<dd>The optional <code>read_bytes_sec_max</code> element is the
|
|
maximum read throughput limit in bytes per second.</dd>
|
|
<dt><code>write_bytes_sec_max</code></dt>
|
|
<dd>The optional <code>write_bytes_sec_max</code> element is the
|
|
maximum write throughput limit in bytes per second.</dd>
|
|
<dt><code>total_iops_sec_max</code></dt>
|
|
<dd>The optional <code>total_iops_sec_max</code> element is the
|
|
maximum total I/O operations per second. This cannot
|
|
appear with <code>read_iops_sec_max</code>
|
|
or <code>write_iops_sec_max</code>.</dd>
|
|
<dt><code>read_iops_sec_max</code></dt>
|
|
<dd>The optional <code>read_iops_sec_max</code> element is the
|
|
maximum read I/O operations per second.</dd>
|
|
<dt><code>write_iops_sec_max</code></dt>
|
|
<dd>The optional <code>write_iops_sec_max</code> element is the
|
|
maximum write I/O operations per second.</dd>
|
|
<dt><code>size_iops_sec</code></dt>
|
|
<dd>The optional <code>size_iops_sec</code> element is the
|
|
size of I/O operations per second.</dd>
|
|
</dl>
|
|
</dd>
|
|
<dt><code>driver</code></dt>
|
|
<dd>
|
|
The optional driver element allows specifying further details
|
|
related to the hypervisor driver used to provide the disk.
|
|
<span class="since">Since 0.1.8</span>
|
|
<ul>
|
|
<li>
|
|
If the hypervisor supports multiple backend drivers, then
|
|
the <code>name</code> attribute selects the primary
|
|
backend driver name, while the optional <code>type</code>
|
|
attribute provides the sub-type. For example, xen
|
|
supports a name of "tap", "tap2", "phy", or "file", with a
|
|
type of "aio", while qemu only supports a name of "qemu",
|
|
but multiple types including "raw", "bochs", "qcow2", and
|
|
"qed".
|
|
</li>
|
|
<li>
|
|
The optional <code>cache</code> attribute controls the
|
|
cache mechanism, possible values are "default", "none",
|
|
"writethrough", "writeback", "directsync" (like
|
|
"writethrough", but it bypasses the host page cache) and
|
|
"unsafe" (host may cache all disk io, and sync requests from
|
|
guest are ignored).
|
|
<span class="since">
|
|
Since 0.6.0,
|
|
"directsync" since 0.9.5,
|
|
"unsafe" since 0.9.7
|
|
</span>
|
|
</li>
|
|
<li>
|
|
The optional <code>error_policy</code> attribute controls
|
|
how the hypervisor will behave on a disk read or write
|
|
error, possible values are "stop", "report", "ignore", and
|
|
"enospace".<span class="since">Since 0.8.0, "report" since
|
|
0.9.7</span> The default setting of error_policy is "report".
|
|
There is also an
|
|
optional <code>rerror_policy</code> that controls behavior
|
|
for read errors only. <span class="since">Since
|
|
0.9.7</span>. If no rerror_policy is given, error_policy
|
|
is used for both read and write errors. If rerror_policy
|
|
is given, it overrides the <code>error_policy</code> for
|
|
read errors. Also note that "enospace" is not a valid
|
|
policy for read errors, so if <code>error_policy</code> is
|
|
set to "enospace" and no <code>rerror_policy</code> is
|
|
given, the read error policy will be left at its default,
|
|
which is "report".
|
|
</li>
|
|
<li>
|
|
The optional <code>io</code> attribute controls specific
|
|
policies on I/O; qemu guests support "threads" and
|
|
"native". <span class="since">Since 0.8.8</span>
|
|
</li>
|
|
<li>
|
|
The optional <code>ioeventfd</code> attribute allows users to
|
|
set <a href='https://patchwork.kernel.org/patch/43390/'>
|
|
domain I/O asynchronous handling</a> for disk device.
|
|
The default is left to the discretion of the hypervisor.
|
|
Accepted values are "on" and "off". Enabling this allows
|
|
qemu to execute VM while a separate thread handles I/O.
|
|
Typically guests experiencing high system CPU utilization
|
|
during I/O will benefit from this. On the other hand,
|
|
on overloaded host it could increase guest I/O latency.
|
|
<span class="since">Since 0.9.3 (QEMU and KVM only)</span>
|
|
<b>In general you should leave this option alone, unless you
|
|
are very certain you know what you are doing.</b>
|
|
</li>
|
|
<li>
|
|
The optional <code>event_idx</code> attribute controls
|
|
some aspects of device event processing. The value can be
|
|
either 'on' or 'off' - if it is on, it will reduce the
|
|
number of interrupts and exits for the guest. The default
|
|
is determined by QEMU; usually if the feature is
|
|
supported, default is on. In case there is a situation
|
|
where this behavior is suboptimal, this attribute provides
|
|
a way to force the feature off.
|
|
<span class="since">Since 0.9.5 (QEMU and KVM only)</span>
|
|
<b>In general you should leave this option alone, unless you
|
|
are very certain you know what you are doing.</b>
|
|
</li>
|
|
<li>
|
|
The optional <code>copy_on_read</code> attribute controls
|
|
whether to copy read backing file into the image file. The
|
|
value can be either "on" or "off".
|
|
Copy-on-read avoids accessing the same backing file sectors
|
|
repeatedly and is useful when the backing file is over a slow
|
|
network. By default copy-on-read is off.
|
|
<span class='since'>Since 0.9.10 (QEMU and KVM only)</span>
|
|
</li>
|
|
<li>
|
|
The optional <code>discard</code> attribute controls whether
|
|
to discard (also known as "trim" or "unmap") requests are
|
|
ignored or passed to the filesystem. The value can be either
|
|
"unmap" (allow the discard request to be passed) or "ignore"
|
|
(ignore the discard request).
|
|
<span class='since'>Since 1.0.6 (QEMU and KVM only)</span>
|
|
</li>
|
|
<li>
|
|
The optional <code>iothread</code> attribute assigns the
|
|
disk to an IOThread as defined by the range for the domain
|
|
<a href="#elementsIOThreadsAllocation"><code>iothreads</code></a>
|
|
value. Multiple devices may be assigned to the same IOThread and
|
|
are numbered from 1 to the domain iothreads value.
|
|
<span class='since'>Since 1.2.8 (QEMU only)</span>
|
|
</li>
|
|
</ul>
|
|
</dd>
|
|
<dt><code>backenddomain</code></dt>
|
|
<dd>The optional <code>backenddomain</code> element allows specifying a
|
|
backend domain (aka driver domain) hosting the disk. Use the
|
|
<code>name</code> attribute to specify the backend domain name.
|
|
<span class="since">Since 1.2.13 (Xen only)</span>
|
|
</dd>
|
|
<dt><code>boot</code></dt>
|
|
<dd>Specifies that the disk is bootable. The <code>order</code>
|
|
attribute determines the order in which devices will be tried during
|
|
boot sequence. The per-device <code>boot</code> elements cannot be
|
|
used together with general boot elements in
|
|
<a href="#elementsOSBIOS">BIOS bootloader</a> section.
|
|
<span class="since">Since 0.8.8</span>
|
|
</dd>
|
|
<dt><code>encryption</code></dt>
|
|
<dd>If present, specifies how the volume is encrypted. See
|
|
the <a href="formatstorageencryption.html">Storage Encryption</a> page
|
|
for more information.
|
|
</dd>
|
|
<dt><code>readonly</code></dt>
|
|
<dd>If present, this indicates the device cannot be modified by
|
|
the guest. For now, this is the default for disks with
|
|
attribute <code>device='cdrom'</code>.
|
|
</dd>
|
|
<dt><code>shareable</code></dt>
|
|
<dd>If present, this indicates the device is expected to be shared
|
|
between domains (assuming the hypervisor and OS support this),
|
|
which means that caching should be deactivated for that device.
|
|
</dd>
|
|
<dt><code>transient</code></dt>
|
|
<dd>If present, this indicates that changes to the device
|
|
contents should be reverted automatically when the guest
|
|
exits. With some hypervisors, marking a disk transient
|
|
prevents the domain from participating in migration or
|
|
snapshots. <span class="since">Since 0.9.5</span>
|
|
</dd>
|
|
<dt><code>serial</code></dt>
|
|
<dd>If present, this specify serial number of virtual hard drive.
|
|
For example, it may look
|
|
like <code><serial>WD-WMAP9A966149</serial></code>.
|
|
<span class="since">Since 0.7.1</span>
|
|
</dd>
|
|
<dt><code>wwn</code></dt>
|
|
<dd>If present, this element specifies the WWN (World Wide Name)
|
|
of a virtual hard disk or CD-ROM drive. It must be composed
|
|
of 16 hexadecimal digits.
|
|
<span class='since'>Since 0.10.1</span>
|
|
</dd>
|
|
<dt><code>vendor</code></dt>
|
|
<dd>If present, this element specifies the vendor of a virtual hard
|
|
disk or CD-ROM device. It must not be longer than 8 printable
|
|
characters.
|
|
<span class='since'>Since 1.0.1</span>
|
|
</dd>
|
|
<dt><code>product</code></dt>
|
|
<dd>If present, this element specifies the product of a virtual hard
|
|
disk or CD-ROM device. It must not be longer than 16 printable
|
|
characters.
|
|
<span class='since'>Since 1.0.1</span>
|
|
</dd>
|
|
<dt><code>address</code></dt>
|
|
<dd>If present, the <code>address</code> element ties the disk
|
|
to a given slot of a controller (the
|
|
actual <code><controller></code> device can often be
|
|
inferred by libvirt, although it can
|
|
be <a href="#elementsControllers">explicitly specified</a>).
|
|
The <code>type</code> attribute is mandatory, and is typically
|
|
"pci" or "drive". For a "pci" controller, additional
|
|
attributes for <code>bus</code>, <code>slot</code>,
|
|
and <code>function</code> must be present, as well as
|
|
optional <code>domain</code> and <code>multifunction</code>.
|
|
Multifunction defaults to 'off'; any other value requires
|
|
QEMU 0.1.3 and <span class="since">libvirt 0.9.7</span>. For a
|
|
"drive" controller, additional attributes
|
|
<code>controller</code>, <code>bus</code>, <code>target</code>
|
|
(<span class="since">libvirt 0.9.11</span>), and <code>unit</code>
|
|
are available, each defaulting to 0.
|
|
</dd>
|
|
<dt><code>auth</code></dt>
|
|
<dd>The <code>auth</code> element is supported for a disk
|
|
<code>type</code> "network" that is using a <code>source</code>
|
|
element with the <code>protocol</code> attributes "rbd" or "iscsi".
|
|
If present, the <code>auth</code> element provides the
|
|
authentication credentials needed to access the source. It
|
|
includes a mandatory attribute <code>username</code>, which
|
|
identifies the username to use during authentication, as well
|
|
as a sub-element <code>secret</code> with mandatory
|
|
attribute <code>type</code>, to tie back to
|
|
a <a href="formatsecret.html">libvirt secret object</a> that
|
|
holds the actual password or other credentials (the domain XML
|
|
intentionally does not expose the password, only the reference
|
|
to the object that does manage the password).
|
|
Known secret types are "ceph" for Ceph RBD network sources and
|
|
"iscsi" for CHAP authentication of iSCSI targets.
|
|
Both will require either a <code>uuid</code> attribute
|
|
with the UUID of the secret object or a <code>usage</code>
|
|
attribute matching the key that was specified in the
|
|
secret object. <span class="since">libvirt 0.9.7</span>
|
|
</dd>
|
|
<dt><code>geometry</code></dt>
|
|
<dd>The optional <code>geometry</code> element provides the
|
|
ability to override geometry settings. This mostly useful for
|
|
S390 DASD-disks or older DOS-disks. <span class="since">0.10.0</span>
|
|
<dl>
|
|
<dt><code>cyls</code></dt>
|
|
<dd>The <code>cyls</code> attribute is the
|
|
number of cylinders. </dd>
|
|
<dt><code>heads</code></dt>
|
|
<dd>The <code>heads</code> attribute is the
|
|
number of heads. </dd>
|
|
<dt><code>secs</code></dt>
|
|
<dd>The <code>secs</code> attribute is the
|
|
number of sectors per track. </dd>
|
|
<dt><code>trans</code></dt>
|
|
<dd>The optional <code>trans</code> attribute is the
|
|
BIOS-Translation-Modus (none, lba or auto)</dd>
|
|
</dl>
|
|
</dd>
|
|
<dt><code>blockio</code></dt>
|
|
<dd>If present, the <code>blockio</code> element allows
|
|
to override any of the block device properties listed below.
|
|
<span class="since">Since 0.10.2 (QEMU and KVM)</span>
|
|
<dl>
|
|
<dt><code>logical_block_size</code></dt>
|
|
<dd>The logical block size the disk will report to the guest
|
|
OS. For Linux this would be the value returned by the
|
|
BLKSSZGET ioctl and describes the smallest units for disk
|
|
I/O.
|
|
</dd>
|
|
<dt><code>physical_block_size</code></dt>
|
|
<dd>The physical block size the disk will report to the guest
|
|
OS. For Linux this would be the value returned by the
|
|
BLKPBSZGET ioctl and describes the disk's hardware sector
|
|
size which can be relevant for the alignment of disk data.
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsFilesystems">Filesystems</a></h4>
|
|
|
|
<p>
|
|
A directory on the host that can be accessed directly from the guest.
|
|
<span class="since">since 0.3.3, since 0.8.5 for QEMU/KVM</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<filesystem type='template'>
|
|
<source name='my-vm-template'/>
|
|
<target dir='/'/>
|
|
</filesystem>
|
|
<filesystem type='mount' accessmode='passthrough'>
|
|
<driver type='path' wrpolicy='immediate'/>
|
|
<source dir='/export/to/guest'/>
|
|
<target dir='/import/from/host'/>
|
|
<readonly/>
|
|
</filesystem>
|
|
<filesystem type='file' accessmode='passthrough'>
|
|
<driver name='loop' type='raw'/>
|
|
<driver type='path' wrpolicy='immediate'/>
|
|
<source file='/export/to/guest.img'/>
|
|
<target dir='/import/from/host'/>
|
|
<readonly/>
|
|
</filesystem>
|
|
...
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>filesystem</code></dt>
|
|
<dd>
|
|
|
|
The filesystem attribute <code>type</code> specifies the type of the
|
|
<code>source</code>. The possible values are:
|
|
|
|
<dl>
|
|
<dt><code>type='mount'</code></dt>
|
|
<dd>
|
|
A host directory to mount in the guest. Used by LXC,
|
|
OpenVZ <span class="since">(since 0.6.2)</span>
|
|
and QEMU/KVM <span class="since">(since 0.8.5)</span>.
|
|
This is the default <code>type</code> if one is not specified.
|
|
This mode also has an optional
|
|
sub-element <code>driver</code>, with an
|
|
attribute <code>type='path'</code>
|
|
or <code>type='handle'</code> <span class="since">(since
|
|
0.9.7)</span>. The driver block has an optional attribute
|
|
<code>wrpolicy</code> that further controls interaction with
|
|
the host page cache; omitting the attribute gives default behavior,
|
|
while the value <code>immediate</code> means that a host writeback
|
|
is immediately triggered for all pages touched during a guest file
|
|
write operation <span class="since">(since 0.9.10)</span>.
|
|
</dd>
|
|
<dt><code>type='template'</code></dt>
|
|
<dd>
|
|
OpenVZ filesystem template. Only used by OpenVZ driver.
|
|
</dd>
|
|
<dt><code>type='file'</code></dt>
|
|
<dd>
|
|
A host file will be treated as an image and mounted in
|
|
the guest. The filesystem format will be autodetected.
|
|
Only used by LXC driver.
|
|
</dd>
|
|
<dt><code>type='block'</code></dt>
|
|
<dd>
|
|
A host block device to mount in the guest. The filesystem
|
|
format will be autodetected. Only used by LXC driver
|
|
<span class="since">(since 0.9.5)</span>.
|
|
</dd>
|
|
<dt><code>type='ram'</code></dt>
|
|
<dd>
|
|
An in-memory filesystem, using memory from the host OS.
|
|
The source element has a single attribute <code>usage</code>
|
|
which gives the memory usage limit in KiB, unless units
|
|
are specified by the <code>units</code> attribute. Only used
|
|
by LXC driver.
|
|
<span class="since"> (since 0.9.13)</span></dd>
|
|
<dt><code>type='bind'</code></dt>
|
|
<dd>
|
|
A directory inside the guest will be bound to another
|
|
directory inside the guest. Only used by LXC driver
|
|
<span class="since"> (since 0.9.13)</span></dd>
|
|
</dl>
|
|
|
|
The filesystem block has an optional attribute <code>accessmode</code>
|
|
which specifies the security mode for accessing the source
|
|
<span class="since">(since 0.8.5)</span>. Currently this only works
|
|
with <code>type='mount'</code> for the QEMU/KVM driver. The possible
|
|
values are:
|
|
|
|
<dl>
|
|
<dt><code>accessmode='passthrough'</code></dt>
|
|
<dd>
|
|
The <code>source</code> is accessed with the permissions of the
|
|
user inside the guest. This is the default <code>accessmode</code> if
|
|
one is not specified.
|
|
<a href="http://lists.gnu.org/archive/html/qemu-devel/2010-05/msg02673.html">More info</a>
|
|
</dd>
|
|
<dt><code>accessmode='mapped'</code></dt>
|
|
<dd>
|
|
The <code>source</code> is accessed with the permissions of the
|
|
hypervisor (QEMU process).
|
|
<a href="http://lists.gnu.org/archive/html/qemu-devel/2010-05/msg02673.html">More info</a>
|
|
</dd>
|
|
<dt><code>accessmode='squash'</code></dt>
|
|
<dd>
|
|
Similar to 'passthrough', the exception is that failure of
|
|
privileged operations like 'chown' are ignored. This makes a
|
|
passthrough-like mode usable for people who run the hypervisor
|
|
as non-root.
|
|
<a href="http://lists.gnu.org/archive/html/qemu-devel/2010-09/msg00121.html">More info</a>
|
|
</dd>
|
|
</dl>
|
|
|
|
</dd>
|
|
|
|
<dt><code>driver</code></dt>
|
|
<dd>
|
|
The optional driver element allows specifying further details
|
|
related to the hypervisor driver used to provide the filesystem.
|
|
<span class="since">Since 1.0.6</span>
|
|
<ul>
|
|
<li>
|
|
If the hypervisor supports multiple backend drivers, then
|
|
the <code>type</code> attribute selects the primary
|
|
backend driver name, while the <code>format</code>
|
|
attribute provides the format type. For example, LXC
|
|
supports a type of "loop", with a format of "raw" or
|
|
"nbd" with any format. QEMU supports a type of "path"
|
|
or "handle", but no formats. Parallels driver supports
|
|
a type of "ploop" with a format of "ploop".
|
|
</li>
|
|
</ul>
|
|
</dd>
|
|
|
|
<dt><code>source</code></dt>
|
|
<dd>
|
|
The resource on the host that is being accessed in the guest. The
|
|
<code>name</code> attribute must be used with
|
|
<code>type='template'</code>, and the <code>dir</code> attribute must
|
|
be used with <code>type='mount'</code>. The <code>usage</code> attribute
|
|
is used with <code>type='ram'</code> to set the memory limit in KiB,
|
|
unless units are specified by the <code>units</code> attribute.
|
|
</dd>
|
|
|
|
<dt><code>target</code></dt>
|
|
<dd>
|
|
Where the <code>source</code> can be accessed in the guest. For
|
|
most drivers this is an automatic mount point, but for QEMU/KVM
|
|
this is merely an arbitrary string tag that is exported to the
|
|
guest as a hint for where to mount.
|
|
</dd>
|
|
|
|
<dt><code>readonly</code></dt>
|
|
<dd>
|
|
Enables exporting filesystem as a readonly mount for guest, by
|
|
default read-write access is given (currently only works for
|
|
QEMU/KVM driver).
|
|
</dd>
|
|
|
|
<dt><code>space_hard_limit</code></dt>
|
|
<dd>
|
|
Maximum space available to this guest's filesystem.
|
|
<span class="since">Since 0.9.13</span>
|
|
</dd>
|
|
|
|
<dt><code>space_soft_limit</code></dt>
|
|
<dd>
|
|
Maximum space available to this guest's filesystem. The container is
|
|
permitted to exceed its soft limits for a grace period of time. Afterwards the
|
|
hard limit is enforced.
|
|
<span class="since">Since 0.9.13</span>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsAddress">Device Addresses</a></h4>
|
|
|
|
<p>
|
|
Many devices have an optional <code><address></code>
|
|
sub-element to describe where the device is placed on the
|
|
virtual bus presented to the guest. If an address (or any
|
|
optional attribute within an address) is omitted on
|
|
input, libvirt will generate an appropriate address; but an
|
|
explicit address is required if more control over layout is
|
|
required. See below for device examples including an address
|
|
element.
|
|
</p>
|
|
|
|
<p>
|
|
Every address has a mandatory attribute <code>type</code> that
|
|
describes which bus the device is on. The choice of which
|
|
address to use for a given device is constrained in part by the
|
|
device and the architecture of the guest. For example,
|
|
a <code><disk></code> device
|
|
uses <code>type='drive'</code>, while
|
|
a <code><console></code> device would
|
|
use <code>type='pci'</code> on i686 or x86_64 guests,
|
|
or <code>type='spapr-vio'</code> on PowerPC64 pseries guests.
|
|
Each address type has further optional attributes that control
|
|
where on the bus the device will be placed:
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>type='pci'</code></dt>
|
|
<dd>PCI addresses have the following additional
|
|
attributes: <code>domain</code> (a 2-byte hex integer, not
|
|
currently used by qemu), <code>bus</code> (a hex value between
|
|
0 and 0xff, inclusive), <code>slot</code> (a hex value between
|
|
0x0 and 0x1f, inclusive), and <code>function</code> (a value
|
|
between 0 and 7, inclusive). Also available is
|
|
the <code>multifunction</code> attribute, which controls
|
|
turning on the multifunction bit for a particular
|
|
slot/function in the PCI control register
|
|
(<span class="since">since 0.9.7, requires QEMU
|
|
0.13</span>). <code>multifunction</code> defaults to 'off',
|
|
but should be set to 'on' for function 0 of a slot that will
|
|
have multiple functions used.
|
|
</dd>
|
|
<dt><code>type='drive'</code></dt>
|
|
<dd>Drive addresses have the following additional
|
|
attributes: <code>controller</code> (a 2-digit controller
|
|
number), <code>bus</code> (a 2-digit bus number),
|
|
<code>target</code> (a 2-digit bus number),
|
|
and <code>unit</code> (a 2-digit unit number on the bus).
|
|
</dd>
|
|
<dt><code>type='virtio-serial'</code></dt>
|
|
<dd>Each virtio-serial address has the following additional
|
|
attributes: <code>controller</code> (a 2-digit controller
|
|
number), <code>bus</code> (a 2-digit bus number),
|
|
and <code>slot</code> (a 2-digit slot within the bus).
|
|
</dd>
|
|
<dt><code>type='ccid'</code></dt>
|
|
<dd>A CCID address, for smart-cards, has the following
|
|
additional attributes: <code>bus</code> (a 2-digit bus
|
|
number), and <code>slot</code> attribute (a 2-digit slot
|
|
within the bus). <span class="since">Since 0.8.8.</span>
|
|
</dd>
|
|
<dt><code>type='usb'</code></dt>
|
|
<dd>USB addresses have the following additional
|
|
attributes: <code>bus</code> (a hex value between 0 and 0xfff,
|
|
inclusive), and <code>port</code> (a dotted notation of up to
|
|
four octets, such as 1.2 or 2.1.3.1).
|
|
</dd>
|
|
<dt><code>type='spapr-vio'</code></dt>
|
|
<dd>On PowerPC pseries guests, devices can be assigned to the
|
|
SPAPR-VIO bus. It has a flat 64-bit address space; by
|
|
convention, devices are generally assigned at a non-zero
|
|
multiple of 0x1000, but other addresses are valid and
|
|
permitted by libvirt. Each address has the following
|
|
additional attribute: <code>reg</code> (the hex value address
|
|
of the starting register). <span class="since">Since
|
|
0.9.9.</span>
|
|
</dd>
|
|
<dt><code>type='ccw'</code></dt>
|
|
<dd>s390 guests with a <code>machine</code> value of
|
|
s390-ccw-virtio use the native CCW bus for I/O devices.
|
|
CCW bus addresses have the following additional attributes:
|
|
<code>cssid</code> (a hex value between 0 and 0xfe, inclusive),
|
|
<code>ssid</code> (a value between 0 and 3, inclusive) and
|
|
<code>devno</code> (a hex value between 0 and 0xffff, inclusive).
|
|
Partially specified bus addresses are not allowed.
|
|
If omitted, libvirt will assign a free bus address with
|
|
cssid=0xfe and ssid=0. Virtio-ccw devices must have their cssid
|
|
set to 0xfe.
|
|
<span class="since">Since 1.0.4</span>
|
|
</dd>
|
|
<dt><code>type='isa'</code></dt>
|
|
<dd>ISA addresses have the following additional
|
|
attributes: <code>iobase</code> and <code>irq</code>.
|
|
<span class="since">Since 1.2.1</span>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsControllers">Controllers</a></h4>
|
|
|
|
<p>
|
|
Depending on the guest architecture, some device buses can
|
|
appear more than once, with a group of virtual devices tied to a
|
|
virtual controller. Normally, libvirt can automatically infer such
|
|
controllers without requiring explicit XML markup, but sometimes
|
|
it is necessary to provide an explicit controller element.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<controller type='ide' index='0'/>
|
|
<controller type='virtio-serial' index='0' ports='16' vectors='4'/>
|
|
<controller type='virtio-serial' index='1'>
|
|
<address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>
|
|
</controller>
|
|
...
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
Each controller has a mandatory attribute <code>type</code>,
|
|
which must be one of "ide", "fdc", "scsi", "sata", "usb",
|
|
"ccid", "virtio-serial" or "pci", and a mandatory
|
|
attribute <code>index</code> which is the decimal integer
|
|
describing in which order the bus controller is encountered (for
|
|
use in <code>controller</code> attributes
|
|
of <code><address></code> elements). The "virtio-serial"
|
|
controller has two additional optional
|
|
attributes <code>ports</code> and <code>vectors</code>, which
|
|
control how many devices can be connected through the
|
|
controller. A "scsi" controller has an optional
|
|
attribute <code>model</code>, which is one of "auto", "buslogic",
|
|
"ibmvscsi", "lsilogic", "lsisas1068", "lsisas1078", "virtio-scsi" or
|
|
"vmpvscsi". A "usb" controller has an optional attribute
|
|
<code>model</code>, which is one of "piix3-uhci", "piix4-uhci", "ehci",
|
|
"ich9-ehci1", "ich9-uhci1", "ich9-uhci2", "ich9-uhci3", "vt82c686b-uhci",
|
|
"pci-ohci" or "nec-xhci". Additionally,
|
|
<span class="since">since 0.10.0</span>, if the USB bus needs to be
|
|
explicitly disabled for the guest, <code>model='none'</code> may be
|
|
used. <span class="since">Since 1.0.5</span>, no default USB controller
|
|
will be built on s390. The PowerPC64 "spapr-vio" addresses do not have an
|
|
associated controller.
|
|
</p>
|
|
|
|
<p>
|
|
For controllers that are themselves devices on a PCI or USB bus,
|
|
an optional sub-element <code><address></code> can specify
|
|
the exact relationship of the controller to its master bus, with
|
|
semantics <a href="#elementsAddress">given above</a>.
|
|
</p>
|
|
|
|
<p>
|
|
An optional sub-element <code>driver</code> can specify the driver
|
|
specific options:
|
|
</p>
|
|
<dl>
|
|
<dt><code>queues</code></dt>
|
|
<dd>
|
|
The optional <code>queues</code> attribute specifies the number of
|
|
queues for the controller. For best performance, it's recommended to
|
|
specify a value matching the number of vCPUs.
|
|
<span class="since">Since 1.0.5 (QEMU and KVM only)</span>
|
|
</dd>
|
|
<dt><code>cmd_per_lun</code></dt>
|
|
<dd>
|
|
The optional <code>cmd_per_lun</code> attribute specifies the maximum
|
|
number of commands that can be queued on devices controlled by the
|
|
host.
|
|
<span class="since">Since 1.2.7 (QEMU and KVM only)</span>
|
|
</dd>
|
|
<dt><code>max_sectors</code></dt>
|
|
<dd>
|
|
The optional <code>max_sectors</code> attribute specifies the maximum
|
|
amount of data in bytes that will be transferred to or from the device
|
|
in a single command. The transfer length is measured in sectors, where
|
|
a sector is 512 bytes.
|
|
<span class="since">Since 1.2.7 (QEMU and KVM only)</span>
|
|
</dd>
|
|
</dl>
|
|
<p>
|
|
USB companion controllers have an optional
|
|
sub-element <code><master></code> to specify the exact
|
|
relationship of the companion to its master controller.
|
|
A companion controller is on the same bus as its master, so
|
|
the companion <code>index</code> value should be equal.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<controller type='usb' index='0' model='ich9-ehci1'>
|
|
<address type='pci' domain='0' bus='0' slot='4' function='7'/>
|
|
</controller>
|
|
<controller type='usb' index='0' model='ich9-uhci1'>
|
|
<master startport='0'/>
|
|
<address type='pci' domain='0' bus='0' slot='4' function='0' multifunction='on'/>
|
|
</controller>
|
|
...
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
PCI controllers have an optional <code>model</code> attribute with
|
|
possible values <code>pci-root</code>, <code>pcie-root</code>,
|
|
<code>pci-bridge</code>, or <code>dmi-to-pci-bridge</code>.
|
|
The root controllers (<code>pci-root</code> and <code>pcie-root</code>)
|
|
have an optional <code>pcihole64</code> element specifying how big
|
|
(in kilobytes, or in the unit specified by <code>pcihole64</code>'s
|
|
<code>unit</code> attribute) the 64-bit PCI hole should be. Some guests (like
|
|
Windows XP or Windows Server 2003) might crash when QEMU and Seabios
|
|
are recent enough to support 64-bit PCI holes, unless this is disabled
|
|
(set to 0). <span class="since">Since 1.1.2 (QEMU only)</span>
|
|
</p>
|
|
<p>
|
|
For machine types which provide an implicit PCI bus, the pci-root
|
|
controller with index=0 is auto-added and required to use PCI devices.
|
|
pci-root has no address.
|
|
PCI bridges are auto-added if there are too many devices to fit on
|
|
the one bus provided by pci-root, or a PCI bus number greater than zero
|
|
was specified.
|
|
PCI bridges can also be specified manually, but their addresses should
|
|
only refer to PCI buses provided by already specified PCI controllers.
|
|
Leaving gaps in the PCI controller indexes might lead to an invalid
|
|
configuration.
|
|
(pci-root and pci-bridge <span class="since">since 1.0.5</span>)
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<controller type='pci' index='0' model='pci-root'/>
|
|
<controller type='pci' index='1' model='pci-bridge'>
|
|
<address type='pci' domain='0' bus='0' slot='5' function='0' multifunction='off'/>
|
|
</controller>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
For machine types which provide an implicit PCI Express (PCIe)
|
|
bus (for example, the machine types based on the Q35 chipset),
|
|
the pcie-root controller with index=0 is auto-added to the
|
|
domain's configuration. pcie-root has also no address, provides
|
|
31 slots (numbered 1-31) and can only be used to attach PCIe
|
|
devices. In order to connect standard PCI devices on a system
|
|
which has a pcie-root controller, a pci controller
|
|
with <code>model='dmi-to-pci-bridge'</code> is automatically
|
|
added. A dmi-to-pci-bridge controller plugs into a PCIe slot (as
|
|
provided by pcie-root), and itself provides 31 standard PCI
|
|
slots (which are not hot-pluggable). In order to have
|
|
hot-pluggable PCI slots in the guest system, a pci-bridge
|
|
controller will also be automatically created and connected to
|
|
one of the slots of the auto-created dmi-to-pci-bridge
|
|
controller; all guest devices with PCI addresses that are
|
|
auto-determined by libvirt will be placed on this pci-bridge
|
|
device. (<span class="since">since 1.1.2</span>).
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<controller type='pci' index='0' model='pcie-root'/>
|
|
<controller type='pci' index='1' model='dmi-to-pci-bridge'>
|
|
<address type='pci' domain='0' bus='0' slot='0xe' function='0'/>
|
|
</controller>
|
|
<controller type='pci' index='2' model='pci-bridge'>
|
|
<address type='pci' domain='0' bus='1' slot='1' function='0'/>
|
|
</controller>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h4><a name="elementsLease">Device leases</a></h4>
|
|
|
|
<p>
|
|
When using a lock manager, it may be desirable to record device leases
|
|
against a VM. The lock manager will ensure the VM won't start unless
|
|
the leases can be acquired.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
...
|
|
<lease>
|
|
<lockspace>somearea</lockspace>
|
|
<key>somekey</key>
|
|
<target path='/some/lease/path' offset='1024'/>
|
|
</lease>
|
|
...
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt>lockspace</dt>
|
|
<dd>This is an arbitrary string, identifying the lockspace
|
|
within which the key is held. Lock managers may impose
|
|
extra restrictions on the format, or length of the lockspace
|
|
name.</dd>
|
|
<dt>key</dt>
|
|
<dd>This is an arbitrary string, uniquely identifying the
|
|
lease to be acquired. Lock managers may impose extra
|
|
restrictions on the format, or length of the key.
|
|
</dd>
|
|
<dt>target</dt>
|
|
<dd>This is the fully qualified path of the file associated
|
|
with the lockspace. The offset specifies where the lease
|
|
is stored within the file. If the lock manager does not
|
|
require a offset, just pass 0.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsHostDev">Host device assignment</a></h4>
|
|
|
|
<h5><a name="elementsHostDevSubsys">USB / PCI / SCSI devices</a></h5>
|
|
|
|
<p>
|
|
USB, PCI and SCSI devices attached to the host can be passed through
|
|
to the guest using the <code>hostdev</code> element.
|
|
<span class="since">since after 0.4.4 for USB, 0.6.0 for PCI(KVM only)
|
|
and 1.0.6 for SCSI(KVM only)</span>:
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<hostdev mode='subsystem' type='usb'>
|
|
<source startupPolicy='optional'>
|
|
<vendor id='0x1234'/>
|
|
<product id='0xbeef'/>
|
|
</source>
|
|
<boot order='2'/>
|
|
</hostdev>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>or:</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<hostdev mode='subsystem' type='pci' managed='yes'>
|
|
<source>
|
|
<address domain='0x0000' bus='0x06' slot='0x02' function='0x0'/>
|
|
</source>
|
|
<boot order='1'/>
|
|
<rom bar='on' file='/etc/fake/boot.bin'/>
|
|
</hostdev>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>or:</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<hostdev mode='subsystem' type='scsi' sgio='filtered' rawio='yes'>
|
|
<source>
|
|
<adapter name='scsi_host0'/>
|
|
<address type='scsi' bus='0' target='0' unit='0'/>
|
|
</source>
|
|
<readonly/>
|
|
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
|
|
</hostdev>
|
|
</devices>
|
|
...</pre>
|
|
|
|
|
|
<p>or:</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<hostdev mode='subsystem' type='scsi'>
|
|
<source protocol='iscsi' name='iqn.2014-08.com.example:iscsi-nopool/1'>
|
|
<host name='example.com' port='3260'/>
|
|
<auth username='myuser'>
|
|
<secret type='iscsi' usage='libvirtiscsi'/>
|
|
</auth>
|
|
</source>
|
|
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
|
|
</hostdev>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>hostdev</code></dt>
|
|
<dd>The <code>hostdev</code> element is the main container for describing
|
|
host devices. For each device, the <code>mode</code> is always
|
|
"subsystem" and the <code>type</code> is one of the following values
|
|
with additional attributes noted.
|
|
<dl>
|
|
<dt>usb</dt>
|
|
<dd>For USB devices, the user is responsible to call
|
|
<code>virNodeDeviceDettach</code> (or
|
|
<code>virsh nodedev-detach</code>) before starting the guest
|
|
or hot-plugging the device and <code>virNodeDeviceReAttach</code>
|
|
(or <code>virsh nodedev-reattach</code>) after hot-unplug or
|
|
stopping the guest.
|
|
</dd>
|
|
<dt>pci</dt>
|
|
<dd>For PCI devices, when <code>managed</code> is "yes" it is
|
|
detached from the host before being passed on to the guest
|
|
and reattached to the host after the guest exits. If
|
|
<code>managed</code> is omitted or "no", follow the steps
|
|
described for a USB device to detach before starting the
|
|
guest or hot-plugging and reattach after stopping the guest
|
|
or hot-unplug.
|
|
</dd>
|
|
<dt>scsi</dt>
|
|
<dd>For SCSI devices, user is responsible to make sure the device
|
|
is not used by host. The optional <code>sgio</code>
|
|
(<span class="since">since 1.0.6</span>) attribute indicates
|
|
whether the kernel will filter unprivileged SG_IO commands for
|
|
the disk, valid settings are "filtered" or "unfiltered".
|
|
The default is "filtered". The optional <code>rawio</code>
|
|
(<span class="since">since 1.2.9</span>) attribute indicates
|
|
whether the lun needs the rawio capability. Valid settings are
|
|
"yes" or "no". See the rawio description within the
|
|
<a href="#elementsDisks">disk</a> section.
|
|
If a disk lun in the domain already has the rawio capability,
|
|
then this setting not required.
|
|
</dd>
|
|
</dl>
|
|
<p>
|
|
Note: The <code>managed</code> attribute is only used with PCI devices
|
|
and is ignored by all the other device types, thus setting
|
|
<code>managed</code> explicitly with other than PCI device has the same
|
|
effect as omitting it.
|
|
</p>
|
|
</dd>
|
|
<dt><code>source</code></dt>
|
|
<dd>The source element describes the device as seen from the host using
|
|
the following mechanism to describe:
|
|
<dl>
|
|
<dt>usb</dt>
|
|
<dd>The USB device can either be addressed by vendor / product id
|
|
using the <code>vendor</code> and <code>product</code> elements
|
|
or by the device's address on the host using the
|
|
<code>address</code> element.
|
|
<p>
|
|
<span class="since">Since 1.0.0</span>, the <code>source</code>
|
|
element of USB devices may contain <code>startupPolicy</code>
|
|
attribute which can be used to define policy what to do if the
|
|
specified host USB device is not found. The attribute accepts
|
|
the following values:
|
|
</p>
|
|
<table class="top_table">
|
|
<tr>
|
|
<td> mandatory </td>
|
|
<td> fail if missing for any reason (the default) </td>
|
|
</tr>
|
|
<tr>
|
|
<td> requisite </td>
|
|
<td> fail if missing on boot up,
|
|
drop if missing on migrate/restore/revert </td>
|
|
</tr>
|
|
<tr>
|
|
<td> optional </td>
|
|
<td> drop if missing at any start attempt </td>
|
|
</tr>
|
|
</table>
|
|
</dd>
|
|
<dt>pci</dt>
|
|
<dd>PCI devices can only be described by their <code>address</code>.
|
|
</dd>
|
|
<dt>scsi</dt>
|
|
<dd>SCSI devices are described by both the <code>adapter</code>
|
|
and <code>address</code> elements.
|
|
<p>
|
|
<span class="since">Since 1.2.8</span>, the <code>source</code>
|
|
element of a SCSI device may contain the <code>protocol</code>
|
|
attribute. When the attribute is set to "iscsi", the host
|
|
device XML follows the network <a href="#elementsDisks">disk</a>
|
|
device using the same <code>name</code> attribute and optionally
|
|
using the <code>auth</code> element to provide the authentication
|
|
credentials to the iSCSI server.
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
<dt><code>vendor</code>, <code>product</code></dt>
|
|
<dd>The <code>vendor</code> and <code>product</code> elements each have an
|
|
<code>id</code> attribute that specifies the USB vendor and product id.
|
|
The ids can be given in decimal, hexadecimal (starting with 0x) or
|
|
octal (starting with 0) form.</dd>
|
|
<dt><code>boot</code></dt>
|
|
<dd>Specifies that the device is bootable. The <code>order</code>
|
|
attribute determines the order in which devices will be tried during
|
|
boot sequence. The per-device <code>boot</code> elements cannot be
|
|
used together with general boot elements in
|
|
<a href="#elementsOSBIOS">BIOS bootloader</a> section.
|
|
<span class="since">Since 0.8.8</span> for PCI devices,
|
|
<span class="since">Since 1.0.1</span> for USB devices.
|
|
</dd>
|
|
<dt><code>rom</code></dt>
|
|
<dd>The <code>rom</code> element is used to change how a PCI
|
|
device's ROM is presented to the guest. The optional <code>bar</code>
|
|
attribute can be set to "on" or "off", and determines whether
|
|
or not the device's ROM will be visible in the guest's memory
|
|
map. (In PCI documentation, the "rombar" setting controls the
|
|
presence of the Base Address Register for the ROM). If no rom
|
|
bar is specified, the qemu default will be used (older
|
|
versions of qemu used a default of "off", while newer qemus
|
|
have a default of "on"). <span class="since">Since
|
|
0.9.7 (QEMU and KVM only)</span>. The optional
|
|
<code>file</code> attribute is used to point to a binary file
|
|
to be presented to the guest as the device's ROM BIOS. This
|
|
can be useful, for example, to provide a PXE boot ROM for a
|
|
virtual function of an sr-iov capable ethernet device (which
|
|
has no boot ROMs for the VFs).
|
|
<span class="since">Since 0.9.10 (QEMU and KVM only)</span>.
|
|
</dd>
|
|
<dt><code>address</code></dt>
|
|
<dd>The <code>address</code> element for USB devices has a
|
|
<code>bus</code> and <code>device</code> attribute to specify the
|
|
USB bus and device number the device appears at on the host.
|
|
The values of these attributes can be given in decimal, hexadecimal
|
|
(starting with 0x) or octal (starting with 0) form.
|
|
For PCI devices the element carries 4 attributes allowing to designate
|
|
the device as can be found with the <code>lspci</code> or
|
|
with <code>virsh
|
|
nodedev-list</code>. <a href="#elementsAddress">See above</a> for
|
|
more details on the address element.</dd>
|
|
<dt><code>driver</code></dt>
|
|
<dd>
|
|
PCI devices can have an optional <code>driver</code>
|
|
subelement that specifies which backend driver to use for PCI
|
|
device assignment. Use the <code>name</code> attribute to
|
|
select either "vfio" (for the new VFIO device assignment
|
|
backend, which is compatible with UEFI SecureBoot) or "kvm"
|
|
(the legacy device assignment handled directly by the KVM
|
|
kernel module)<span class="since">Since 1.0.5 (QEMU and KVM
|
|
only, requires kernel 3.6 or newer)</span>. When specified,
|
|
device assignment will fail if the requested method of device
|
|
assignment isn't available on the host. When not specified,
|
|
the default is "vfio" on systems where the VFIO driver is
|
|
available and loaded, and "kvm" on older systems, or those
|
|
where the VFIO driver hasn't been
|
|
loaded <span class="since">Since 1.1.3</span> (prior to that
|
|
the default was always "kvm").
|
|
</dd>
|
|
<dt><code>readonly</code></dt>
|
|
<dd>Indicates that the device is readonly, only supported by SCSI host
|
|
device now. <span class="since">Since 1.0.6 (QEMU and KVM only)</span>
|
|
</dd>
|
|
<dt><code>shareable</code></dt>
|
|
<dd>If present, this indicates the device is expected to be shared
|
|
between domains (assuming the hypervisor and OS support this).
|
|
Only supported by SCSI host device.
|
|
<span class="since">Since 1.0.6</span>
|
|
<p>
|
|
Note: Although <code>shareable</code> was introduced
|
|
<span class="since">in 1.0.6</span>, it did not work as
|
|
as expected until <span class="since">1.2.2</span>.
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
|
|
<h5><a name="elementsHostDevCaps">Block / character devices</a></h5>
|
|
|
|
<p>
|
|
Block / character devices from the host can be passed through
|
|
to the guest using the <code>hostdev</code> element. This is
|
|
only possible with container based virtualization.
|
|
<span class="since">since after 1.0.1 for LXC</span>:
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<hostdev mode='capabilities' type='storage'>
|
|
<source>
|
|
<block>/dev/sdf1</block>
|
|
</source>
|
|
</hostdev>
|
|
...
|
|
</pre>
|
|
|
|
<pre>
|
|
...
|
|
<hostdev mode='capabilities' type='misc'>
|
|
<source>
|
|
<char>/dev/input/event3</char>
|
|
</source>
|
|
</hostdev>
|
|
...
|
|
</pre>
|
|
|
|
<pre>
|
|
...
|
|
<hostdev mode='capabilities' type='net'>
|
|
<source>
|
|
<interface>eth0</interface>
|
|
</source>
|
|
</hostdev>
|
|
...
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>hostdev</code></dt>
|
|
<dd>The <code>hostdev</code> element is the main container for describing
|
|
host devices. For block/character device passthrough <code>mode</code> is
|
|
always "capabilities" and <code>type</code> is "storage" for a block
|
|
device, "misc" for a character device and "net" for a host network
|
|
interface.
|
|
</dd>
|
|
<dt><code>source</code></dt>
|
|
<dd>The source element describes the device as seen from the host.
|
|
For block devices, the path to the block device in the host
|
|
OS is provided in the nested "block" element, while for character
|
|
devices the "char" element is used. For network interfaces, the
|
|
name of the interface is provided in the "interface" element.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsRedir">Redirected devices</a></h4>
|
|
|
|
<p>
|
|
USB device redirection through a character device is
|
|
supported <span class="since">since after 0.9.5 (KVM
|
|
only)</span>:
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<redirdev bus='usb' type='tcp'>
|
|
<source mode='connect' host='localhost' service='4000'/>
|
|
<boot order='1'/>
|
|
</redirdev>
|
|
<redirfilter>
|
|
<usbdev class='0x08' vendor='0x1234' product='0xbeef' version='2.56' allow='yes'/>
|
|
<usbdev allow='no'/>
|
|
</redirfilter>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>redirdev</code></dt>
|
|
<dd>The <code>redirdev</code> element is the main container for
|
|
describing redirected devices. <code>bus</code> must be "usb"
|
|
for a USB device.
|
|
|
|
An additional attribute <code>type</code> is required,
|
|
matching one of the
|
|
supported <a href="#elementsConsole">serial device</a> types,
|
|
to describe the host side of the
|
|
tunnel; <code>type='tcp'</code>
|
|
or <code>type='spicevmc'</code> (which uses the usbredir
|
|
channel of a <a href="#elementsGraphics">SPICE graphics
|
|
device</a>) are typical. The redirdev element has an optional
|
|
sub-element <code><address></code> which can tie the
|
|
device to a particular controller. Further sub-elements,
|
|
such as <code><source></code>, may be required according
|
|
to the given type, although a <code><target></code> sub-element
|
|
is not required (since the consumer of the character device is
|
|
the hypervisor itself, rather than a device visible in the guest).
|
|
</dd>
|
|
<dt><code>boot</code></dt>
|
|
|
|
<dd>Specifies that the device is bootable.
|
|
The <code>order</code> attribute determines the order in which
|
|
devices will be tried during boot sequence. The per-device
|
|
<code>boot</code> elements cannot be used together with general
|
|
boot elements in <a href="#elementsOSBIOS">BIOS bootloader</a> section.
|
|
(<span class="since">Since 1.0.1</span>)
|
|
</dd>
|
|
<dt><code>redirfilter</code></dt>
|
|
<dd>The<code> redirfilter </code>element is used for creating the
|
|
filter rule to filter out certain devices from redirection.
|
|
It uses sub-element <code><usbdev></code> to define each filter rule.
|
|
<code>class</code> attribute is the USB Class code, for example,
|
|
0x08 represents mass storage devices. The USB device can be addressed by
|
|
vendor / product id using the <code>vendor</code> and <code>product</code> attributes.
|
|
<code>version</code> is the device revision from the bcdDevice field (not
|
|
the version of the USB protocol).
|
|
These four attributes are optional and <code>-1</code> can be used to allow
|
|
any value for them. <code>allow</code> attribute is mandatory,
|
|
'yes' means allow, 'no' for deny.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsSmartcard">Smartcard devices</a></h4>
|
|
|
|
<p>
|
|
A virtual smartcard device can be supplied to the guest via the
|
|
<code>smartcard</code> element. A USB smartcard reader device on
|
|
the host cannot be used on a guest with simple device
|
|
passthrough, since it will then not be available on the host,
|
|
possibly locking the host computer when it is "removed".
|
|
Therefore, some hypervisors provide a specialized virtual device
|
|
that can present a smartcard interface to the guest, with
|
|
several modes for describing how credentials are obtained from
|
|
the host or even a from a channel created to a third-party
|
|
smartcard provider. <span class="since">Since 0.8.8</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<smartcard mode='host'/>
|
|
<smartcard mode='host-certificates'>
|
|
<certificate>cert1</certificate>
|
|
<certificate>cert2</certificate>
|
|
<certificate>cert3</certificate>
|
|
<database>/etc/pki/nssdb/</database>
|
|
</smartcard>
|
|
<smartcard mode='passthrough' type='tcp'>
|
|
<source mode='bind' host='127.0.0.1' service='2001'/>
|
|
<protocol type='raw'/>
|
|
<address type='ccid' controller='0' slot='0'/>
|
|
</smartcard>
|
|
<smartcard mode='passthrough' type='spicevmc'/>
|
|
</devices>
|
|
...
|
|
</pre>
|
|
|
|
<p>
|
|
The <code><smartcard></code> element has a mandatory
|
|
attribute <code>mode</code>. The following modes are supported;
|
|
in each mode, the guest sees a device on its USB bus that
|
|
behaves like a physical USB CCID (Chip/Smart Card Interface
|
|
Device) card.
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>mode='host'</code></dt>
|
|
<dd>The simplest operation, where the hypervisor relays all
|
|
requests from the guest into direct access to the host's
|
|
smartcard via NSS. No other attributes or sub-elements are
|
|
required. See below about the use of an
|
|
optional <code><address></code> sub-element.</dd>
|
|
|
|
<dt><code>mode='host-certificates'</code></dt>
|
|
<dd>Rather than requiring a smartcard to be plugged into the
|
|
host, it is possible to provide three NSS certificate names
|
|
residing in a database on the host. These certificates can be
|
|
generated via the command <code>certutil -d /etc/pki/nssdb -x -t
|
|
CT,CT,CT -S -s CN=cert1 -n cert1</code>, and the resulting three
|
|
certificate names must be supplied as the content of each of
|
|
three <code><certificate></code> sub-elements. An
|
|
additional sub-element <code><database></code> can specify
|
|
the absolute path to an alternate directory (matching
|
|
the <code>-d</code> option of the <code>certutil</code> command
|
|
when creating the certificates); if not present, it defaults to
|
|
/etc/pki/nssdb.</dd>
|
|
|
|
<dt><code>mode='passthrough'</code></dt>
|
|
<dd>Rather than having the hypervisor directly communicate with
|
|
the host, it is possible to tunnel all requests through a
|
|
secondary character device to a third-party provider (which may
|
|
in turn be talking to a smartcard or using three certificate
|
|
files). In this mode of operation, an additional
|
|
attribute <code>type</code> is required, matching one of the
|
|
supported <a href="#elementsConsole">serial device</a> types, to
|
|
describe the host side of the tunnel; <code>type='tcp'</code>
|
|
or <code>type='spicevmc'</code> (which uses the smartcard
|
|
channel of a <a href="#elementsGraphics">SPICE graphics
|
|
device</a>) are typical. Further sub-elements, such
|
|
as <code><source></code>, may be required according to the
|
|
given type, although a <code><target></code> sub-element
|
|
is not required (since the consumer of the character device is
|
|
the hypervisor itself, rather than a device visible in the
|
|
guest).</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
Each mode supports an optional
|
|
sub-element <code><address></code>, which fine-tunes the
|
|
correlation between the smartcard and a ccid bus
|
|
controller, <a href="#elementsAddress">documented above</a>.
|
|
For now, qemu only supports at most one
|
|
smartcard, with an address of bus=0 slot=0.
|
|
</p>
|
|
|
|
<h4><a name="elementsNICS">Network interfaces</a></h4>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='direct' trustGuestRxFilters='yes'>
|
|
<source dev='eth0'/>
|
|
<mac address='52:54:00:5d:c7:9e'/>
|
|
<boot order='1'/>
|
|
<rom bar='off'/>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
There are several possibilities for specifying a network
|
|
interface visible to the guest. Each subsection below provides
|
|
more details about common setup options.
|
|
</p>
|
|
<p>
|
|
<span class="since">Since 1.2.10</span>),
|
|
the <code>interface</code> element
|
|
property <code>trustGuestRxFilters</code> provides the
|
|
capability for the host to detect and trust reports from the
|
|
guest regarding changes to the interface mac address and receive
|
|
filters by setting the attribute to <code>yes</code>. The default
|
|
setting for the attribute is <code>no</code> for security
|
|
reasons and support depends on the guest network device model as
|
|
well as the type of connection on the host - currently it is
|
|
only supported for the virtio device model and for macvtap
|
|
connections on the host.
|
|
</p>
|
|
<p>
|
|
Each <code><interface></code> element has an
|
|
optional <code><address></code> sub-element that can tie
|
|
the interface to a particular pci slot, with
|
|
attribute <code>type='pci'</code>
|
|
as <a href="#elementsAddress">documented above</a>.
|
|
</p>
|
|
|
|
<h5><a name="elementsNICSVirtual">Virtual network</a></h5>
|
|
|
|
<p>
|
|
<strong><em>
|
|
This is the recommended config for general guest connectivity on
|
|
hosts with dynamic / wireless networking configs (or multi-host
|
|
environments where the host hardware details are described
|
|
separately in a <code><network></code>
|
|
definition <span class="since">Since 0.9.4</span>).
|
|
</em></strong>
|
|
</p>
|
|
|
|
<p>
|
|
|
|
Provides a connection whose details are described by the named
|
|
network definition. Depending on the virtual network's "forward
|
|
mode" configuration, the network may be totally isolated
|
|
(no <code><forward></code> element given), NAT'ing to an
|
|
explicit network device or to the default route
|
|
(<code><forward mode='nat'></code>), routed with no NAT
|
|
(<code><forward mode='route'/></code>), or connected
|
|
directly to one of the host's network interfaces (via macvtap)
|
|
or bridge devices ((<code><forward
|
|
mode='bridge|private|vepa|passthrough'/></code> <span class="since">Since
|
|
0.9.4</span>)
|
|
</p>
|
|
<p>
|
|
For networks with a forward mode of bridge, private, vepa, and
|
|
passthrough, it is assumed that the host has any necessary DNS
|
|
and DHCP services already setup outside the scope of libvirt. In
|
|
the case of isolated, nat, and routed networks, DHCP and DNS are
|
|
provided on the virtual network by libvirt, and the IP range can
|
|
be determined by examining the virtual network config with
|
|
'<code>virsh net-dumpxml [networkname]</code>'. There is one
|
|
virtual network called 'default' setup out of the box which does
|
|
NAT'ing to the default route and has an IP range
|
|
of <code>192.168.122.0/255.255.255.0</code>. Each guest will
|
|
have an associated tun device created with a name of vnetN,
|
|
which can also be overridden with the <target> element
|
|
(see
|
|
<a href="#elementsNICSTargetOverride">overriding the target element</a>).
|
|
</p>
|
|
<p>
|
|
When the source of an interface is a network,
|
|
a <code>portgroup</code> can be specified along with the name of
|
|
the network; one network may have multiple portgroups defined,
|
|
with each portgroup containing slightly different configuration
|
|
information for different classes of network
|
|
connections. <span class="since">Since 0.9.4</span>.
|
|
</p>
|
|
<p>
|
|
Also, similar to <code>direct</code> network connections
|
|
(described below), a connection of type <code>network</code> may
|
|
specify a <code>virtualport</code> element, with configuration
|
|
data to be forwarded to a vepa (802.1Qbg) or 802.1Qbh compliant
|
|
switch (<span class="since">Since 0.8.2</span>), or to an
|
|
Open vSwitch virtual switch (<span class="since">Since
|
|
0.9.11</span>).
|
|
</p>
|
|
<p>
|
|
Since the actual type of switch may vary depending on the
|
|
configuration in the <code><network></code> on the host,
|
|
it is acceptable to omit the virtualport <code>type</code>
|
|
attribute, and specify attributes from multiple different
|
|
virtualport types (and also to leave out certain attributes); at
|
|
domain startup time, a complete <code><virtualport></code>
|
|
element will be constructed by merging together the type and
|
|
attributes defined in the network and the portgroup referenced
|
|
by the interface. The newly-constructed virtualport is a combination
|
|
of them. The attributes from lower virtualport can't make change
|
|
on the ones defined in higher virtualport.
|
|
Interface takes the highest priority, portgroup is lowest priority.
|
|
(<span class="since">Since 0.10.0</span>). For example, in order
|
|
to work properly with both an 802.1Qbh switch and an Open vSwitch
|
|
switch, you may choose to specify no type, but both
|
|
an <code>profileid</code> (in case the switch is 802.1Qbh) and
|
|
an <code>interfaceid</code> (in case the switch is Open vSwitch)
|
|
(you may also omit the other attributes, such as managerid,
|
|
typeid, or profileid, to be filled in from the
|
|
network's <code><virtualport></code>). If you want to
|
|
limit a guest to connecting only to certain types of switches,
|
|
you can specify the virtualport type, but still omit some/all of
|
|
the parameters - in this case if the host's network has a
|
|
different type of virtualport, connection of the interface will
|
|
fail.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
</interface>
|
|
...
|
|
<interface type='network'>
|
|
<source network='default' portgroup='engineering'/>
|
|
<target dev='vnet7'/>
|
|
<mac address="00:11:22:33:44:55"/>
|
|
<virtualport>
|
|
<parameters instanceid='09b11c53-8b5c-4eeb-8f00-d84eaa0aaa4f'/>
|
|
</virtualport>
|
|
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h5><a name="elementsNICSBridge">Bridge to LAN</a></h5>
|
|
|
|
<p>
|
|
<strong><em>
|
|
This is the recommended config for general guest connectivity on
|
|
hosts with static wired networking configs.
|
|
</em></strong>
|
|
</p>
|
|
|
|
<p>
|
|
Provides a bridge from the VM directly to the LAN. This assumes
|
|
there is a bridge device on the host which has one or more of the hosts
|
|
physical NICs enslaved. The guest VM will have an associated tun device
|
|
created with a name of vnetN, which can also be overridden with the
|
|
<target> element (see
|
|
<a href="#elementsNICSTargetOverride">overriding the target element</a>).
|
|
The tun device will be enslaved to the bridge. The IP range / network
|
|
configuration is whatever is used on the LAN. This provides the guest VM
|
|
full incoming & outgoing net access just like a physical machine.
|
|
</p>
|
|
<p>
|
|
On Linux systems, the bridge device is normally a standard Linux
|
|
host bridge. On hosts that support Open vSwitch, it is also
|
|
possible to connect to an open vSwitch bridge device by adding
|
|
a <code><virtualport type='openvswitch'/></code> to the
|
|
interface definition. (<span class="since">Since
|
|
0.9.11</span>). The Open vSwitch type virtualport accepts two
|
|
parameters in its <code><parameters></code> element -
|
|
an <code>interfaceid</code> which is a standard uuid used to
|
|
uniquely identify this particular interface to Open vSwitch (if
|
|
you do not specify one, a random interfaceid will be generated
|
|
for you when you first define the interface), and an
|
|
optional <code>profileid</code> which is sent to Open vSwitch as
|
|
the interfaces "port-profile".
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
...
|
|
<interface type='bridge'>
|
|
<source bridge='br0'/>
|
|
</interface>
|
|
<interface type='bridge'>
|
|
<source bridge='br1'/>
|
|
<target dev='vnet7'/>
|
|
<mac address="00:11:22:33:44:55"/>
|
|
</interface>
|
|
<interface type='bridge'>
|
|
<source bridge='ovsbr'/>
|
|
<virtualport type='openvswitch'>
|
|
<parameters profileid='menial' interfaceid='09b11c53-8b5c-4eeb-8f00-d84eaa0aaa4f'/>
|
|
</virtualport>
|
|
</interface>
|
|
...
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h5><a name="elementsNICSSlirp">Userspace SLIRP stack</a></h5>
|
|
|
|
<p>
|
|
Provides a virtual LAN with NAT to the outside world. The virtual
|
|
network has DHCP & DNS services and will give the guest VM addresses
|
|
starting from <code>10.0.2.15</code>. The default router will be
|
|
<code>10.0.2.2</code> and the DNS server will be <code>10.0.2.3</code>.
|
|
This networking is the only option for unprivileged users who need their
|
|
VMs to have outgoing access.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='user'/>
|
|
...
|
|
<interface type='user'>
|
|
<mac address="00:11:22:33:44:55"/>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
|
|
<h5><a name="elementsNICSEthernet">Generic ethernet connection</a></h5>
|
|
|
|
<p>
|
|
Provides a means for the administrator to execute an arbitrary script
|
|
to connect the guest's network to the LAN. The guest will have a tun
|
|
device created with a name of vnetN, which can also be overridden with the
|
|
<target> element. After creating the tun device a shell script will
|
|
be run which is expected to do whatever host network integration is
|
|
required. By default this script is called /etc/qemu-ifup but can be
|
|
overridden.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='ethernet'/>
|
|
...
|
|
<interface type='ethernet'>
|
|
<target dev='vnet7'/>
|
|
<script path='/etc/qemu-ifup-mynet'/>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h5><a name="elementsNICSDirect">Direct attachment to physical interface</a></h5>
|
|
|
|
<p>
|
|
Provides direct attachment of the virtual machine's NIC to the given
|
|
physical interface of the host.
|
|
<span class="since">Since 0.7.7 (QEMU and KVM only)</span><br/>
|
|
This setup requires the Linux macvtap
|
|
driver to be available. <span class="since">(Since Linux 2.6.34.)</span>
|
|
One of the modes 'vepa'
|
|
( <a href="http://www.ieee802.org/1/files/public/docs2009/new-evb-congdon-vepa-modular-0709-v01.pdf">
|
|
'Virtual Ethernet Port Aggregator'</a>), 'bridge' or 'private'
|
|
can be chosen for the operation mode of the macvtap device, 'vepa'
|
|
being the default mode. The individual modes cause the delivery of
|
|
packets to behave as follows:
|
|
</p>
|
|
<p>
|
|
If the model type is set to <code>virtio</code> and
|
|
interface's <code>trustGuestRxFilters</code> attribute is set
|
|
to <code>yes</code>, changes made to the interface mac address,
|
|
unicast/multicast receive filters, and vlan settings in the
|
|
guest will be monitored and propagated to the associated macvtap
|
|
device on the host (<span class="since">Since
|
|
1.2.10</span>). If <code>trustGuestRxFilters</code> is not set,
|
|
or is not supported for the device model in use, an attempted
|
|
change to the mac address originating from the guest side will
|
|
result in a non-working network connection.
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>vepa</code></dt>
|
|
<dd>All VMs' packets are sent to the external bridge. Packets
|
|
whose destination is a VM on the same host as where the
|
|
packet originates from are sent back to the host by the VEPA
|
|
capable bridge (today's bridges are typically not VEPA capable).</dd>
|
|
<dt><code>bridge</code></dt>
|
|
<dd>Packets whose destination is on the same host as where they
|
|
originate from are directly delivered to the target macvtap device.
|
|
Both origin and destination devices need to be in bridge mode
|
|
for direct delivery. If either one of them is in <code>vepa</code> mode,
|
|
a VEPA capable bridge is required.</dd>
|
|
<dt><code>private</code></dt>
|
|
<dd>All packets are sent to the external bridge and will only be
|
|
delivered to a target VM on the same host if they are sent through an
|
|
external router or gateway and that device sends them back to the
|
|
host. This procedure is followed if either the source or destination
|
|
device is in <code>private</code> mode.</dd>
|
|
<dt><code>passthrough</code></dt>
|
|
<dd>This feature attaches a virtual function of a SRIOV capable
|
|
NIC directly to a VM without losing the migration capability.
|
|
All packets are sent to the VF/IF of the configured network device.
|
|
Depending on the capabilities of the device additional prerequisites or
|
|
limitations may apply; for example, on Linux this requires
|
|
kernel 2.6.38 or newer. <span class="since">Since 0.9.2</span></dd>
|
|
</dl>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
...
|
|
<interface type='direct' trustGuestRxFilters='no'>
|
|
<source dev='eth0' mode='vepa'/>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
The network access of direct attached virtual machines can be
|
|
managed by the hardware switch to which the physical interface
|
|
of the host machine is connected to.
|
|
</p>
|
|
<p>
|
|
The interface can have additional parameters as shown below,
|
|
if the switch is conforming to the IEEE 802.1Qbg standard.
|
|
The parameters of the virtualport element are documented in more detail
|
|
in the IEEE 802.1Qbg standard. The values are network specific and
|
|
should be provided by the network administrator. In 802.1Qbg terms,
|
|
the Virtual Station Interface (VSI) represents the virtual interface
|
|
of a virtual machine. <span class="since">Since 0.8.2</span>
|
|
</p>
|
|
<p>
|
|
Please note that IEEE 802.1Qbg requires a non-zero value for the
|
|
VLAN ID.
|
|
</p>
|
|
<dl>
|
|
<dt><code>managerid</code></dt>
|
|
<dd>The VSI Manager ID identifies the database containing the VSI type
|
|
and instance definitions. This is an integer value and the
|
|
value 0 is reserved.</dd>
|
|
<dt><code>typeid</code></dt>
|
|
<dd>The VSI Type ID identifies a VSI type characterizing the network
|
|
access. VSI types are typically managed by network administrator.
|
|
This is an integer value.
|
|
</dd>
|
|
<dt><code>typeidversion</code></dt>
|
|
<dd>The VSI Type Version allows multiple versions of a VSI Type.
|
|
This is an integer value.
|
|
</dd>
|
|
<dt><code>instanceid</code></dt>
|
|
<dd>The VSI Instance ID Identifier is generated when a VSI instance
|
|
(i.e. a virtual interface of a virtual machine) is created.
|
|
This is a globally unique identifier.
|
|
</dd>
|
|
</dl>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
...
|
|
<interface type='direct'>
|
|
<source dev='eth0.2' mode='vepa'/>
|
|
<virtualport type="802.1Qbg">
|
|
<parameters managerid="11" typeid="1193047" typeidversion="2" instanceid="09b11c53-8b5c-4eeb-8f00-d84eaa0aaa4f"/>
|
|
</virtualport>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
The interface can have additional parameters as shown below
|
|
if the switch is conforming to the IEEE 802.1Qbh standard.
|
|
The values are network specific and should be provided by the
|
|
network administrator. <span class="since">Since 0.8.2</span>
|
|
</p>
|
|
<dl>
|
|
<dt><code>profileid</code></dt>
|
|
<dd>The profile ID contains the name of the port profile that is to
|
|
be applied to this interface. This name is resolved by the port
|
|
profile database into the network parameters from the port profile,
|
|
and those network parameters will be applied to this interface.
|
|
</dd>
|
|
</dl>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
...
|
|
<interface type='direct'>
|
|
<source dev='eth0' mode='private'/>
|
|
<virtualport type='802.1Qbh'>
|
|
<parameters profileid='finance'/>
|
|
</virtualport>
|
|
</interface>
|
|
</devices>
|
|
...
|
|
</pre>
|
|
|
|
|
|
<h5><a name="elementsNICSHostdev">PCI Passthrough</a></h5>
|
|
|
|
<p>
|
|
A PCI network device (specified by the <source> element)
|
|
is directly assigned to the guest using generic device
|
|
passthrough, after first optionally setting the device's MAC
|
|
address to the configured value, and associating the device with
|
|
an 802.1Qbh capable switch using an optionally specified
|
|
<virtualport> element (see the examples of virtualport
|
|
given above for type='direct' network devices). Note that - due
|
|
to limitations in standard single-port PCI ethernet card driver
|
|
design - only SR-IOV (Single Root I/O Virtualization) virtual
|
|
function (VF) devices can be assigned in this manner; to assign
|
|
a standard single-port PCI or PCIe ethernet card to a guest, use
|
|
the traditional <hostdev> device definition and
|
|
<span class="since">Since 0.9.11</span>
|
|
</p>
|
|
|
|
<p>
|
|
To use VFIO device assignment rather than traditional/legacy KVM
|
|
device assignment (VFIO is a new method of device assignment
|
|
that is compatible with UEFI Secure Boot), a type='hostdev'
|
|
interface can have an optional <code>driver</code> sub-element
|
|
with a <code>name</code> attribute set to "vfio". To use legacy
|
|
KVM device assignment you can set <code>name</code> to "kvm" (or
|
|
simply omit the <code><driver></code> element, since "kvm"
|
|
is currently the default).
|
|
<span class="since">Since 1.0.5 (QEMU and KVM only, requires kernel 3.6 or newer)</span>
|
|
</p>
|
|
|
|
<p>
|
|
Note that this "intelligent passthrough" of network devices is
|
|
very similar to the functionality of a standard <hostdev>
|
|
device, the difference being that this method allows specifying
|
|
a MAC address and <virtualport> for the passed-through
|
|
device. If these capabilities are not required, if you have a
|
|
standard single-port PCI, PCIe, or USB network card that doesn't
|
|
support SR-IOV (and hence would anyway lose the configured MAC
|
|
address during reset after being assigned to the guest domain),
|
|
or if you are using a version of libvirt older than 0.9.11, you
|
|
should use standard <hostdev> to assign the device to the
|
|
guest instead of <interface type='hostdev'/>.
|
|
</p>
|
|
|
|
<p>
|
|
Similar to the functionality of a standard <hostdev> device,
|
|
when <code>managed</code> is "yes", it is detached from the host
|
|
before being passed on to the guest, and reattached to the host
|
|
after the guest exits. If <code>managed</code> is omitted or "no",
|
|
the user is responsible to call <code>virNodeDeviceDettach</code>
|
|
(or <code>virsh nodedev-detach</code>) before starting the guest
|
|
or hot-plugging the device, and <code>virNodeDeviceReAttach</code>
|
|
(or <code>virsh nodedev-reattach</code>) after hot-unplug or
|
|
stopping the guest.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='hostdev' managed='yes'>
|
|
<driver name='vfio'/>
|
|
<source>
|
|
<address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
|
|
</source>
|
|
<mac address='52:54:00:6d:90:02'/>
|
|
<virtualport type='802.1Qbh'>
|
|
<parameters profileid='finance'/>
|
|
</virtualport>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
|
|
<h5><a name="elementsNICSMulticast">Multicast tunnel</a></h5>
|
|
|
|
<p>
|
|
A multicast group is setup to represent a virtual network. Any VMs
|
|
whose network devices are in the same multicast group can talk to each
|
|
other even across hosts. This mode is also available to unprivileged
|
|
users. There is no default DNS or DHCP support and no outgoing network
|
|
access. To provide outgoing network access, one of the VMs should have a
|
|
2nd NIC which is connected to one of the first 4 network types and do the
|
|
appropriate routing. The multicast protocol is compatible with that used
|
|
by user mode linux guests too. The source address used must be from the
|
|
multicast address block.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='mcast'>
|
|
<mac address='52:54:00:6d:90:01'/>
|
|
<source address='230.0.0.1' port='5558'/>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h5><a name="elementsNICSTCP">TCP tunnel</a></h5>
|
|
|
|
<p>
|
|
A TCP client/server architecture provides a virtual network. One VM
|
|
provides the server end of the network, all other VMS are configured as
|
|
clients. All network traffic is routed between the VMs via the server.
|
|
This mode is also available to unprivileged users. There is no default
|
|
DNS or DHCP support and no outgoing network access. To provide outgoing
|
|
network access, one of the VMs should have a 2nd NIC which is connected
|
|
to one of the first 4 network types and do the appropriate routing.</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='server'>
|
|
<mac address='52:54:00:22:c9:42'/>
|
|
<source address='192.168.0.1' port='5558'/>
|
|
</interface>
|
|
...
|
|
<interface type='client'>
|
|
<mac address='52:54:00:8b:c9:51'/>
|
|
<source address='192.168.0.1' port='5558'/>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h5><a name="elementsNICSModel">Setting the NIC model</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet1'/>
|
|
<b><model type='ne2k_pci'/></b>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
For hypervisors which support this, you can set the model of
|
|
emulated network interface card.
|
|
</p>
|
|
|
|
<p>
|
|
The values for <code>type</code> aren't defined specifically by
|
|
libvirt, but by what the underlying hypervisor supports (if
|
|
any). For QEMU and KVM you can get a list of supported models
|
|
with these commands:
|
|
</p>
|
|
|
|
<pre>
|
|
qemu -net nic,model=? /dev/null
|
|
qemu-kvm -net nic,model=? /dev/null
|
|
</pre>
|
|
|
|
<p>
|
|
Typical values for QEMU and KVM include:
|
|
ne2k_isa i82551 i82557b i82559er ne2k_pci pcnet rtl8139 e1000 virtio
|
|
</p>
|
|
|
|
<h5><a name="elementsDriverBackendOptions">Setting NIC driver-specific options</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet1'/>
|
|
<model type='virtio'/>
|
|
<b><driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5'>
|
|
<host csum='off' gso='off' tso4='off' tso6='off' ecn='off' ufo='off' mrg_rxbuf='off'/>
|
|
<guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/>
|
|
</driver>
|
|
</b>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
Some NICs may have tunable driver-specific options. These are
|
|
set as attributes of the <code>driver</code> sub-element of the
|
|
interface definition. Currently the following attributes are
|
|
available for the <code>"virtio"</code> NIC driver:
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>name</code></dt>
|
|
<dd>
|
|
The optional <code>name</code> attribute forces which type of
|
|
backend driver to use. The value can be either 'qemu' (a
|
|
user-space backend) or 'vhost' (a kernel backend, which
|
|
requires the vhost module to be provided by the kernel); an
|
|
attempt to require the vhost driver without kernel support
|
|
will be rejected. If this attribute is not present, then the
|
|
domain defaults to 'vhost' if present, but silently falls back
|
|
to 'qemu' without error.
|
|
<span class="since">Since 0.8.8 (QEMU and KVM only)</span>
|
|
</dd>
|
|
<dd>
|
|
For interfaces of type='hostdev' (PCI passthrough devices)
|
|
the <code>name</code> attribute can optionally be set to
|
|
"vfio" or "kvm". "vfio" tells libvirt to use VFIO device
|
|
assignment rather than traditional KVM device assignment (VFIO
|
|
is a new method of device assignment that is compatible with
|
|
UEFI Secure Boot), and "kvm" tells libvirt to use the legacy
|
|
device assignment performed directly by the kvm kernel module
|
|
(the default is currently "kvm", but is subject to change).
|
|
<span class="since">Since 1.0.5 (QEMU and KVM only, requires
|
|
kernel 3.6 or newer)</span>
|
|
</dd>
|
|
|
|
<dt><code>txmode</code></dt>
|
|
<dd>
|
|
The <code>txmode</code> attribute specifies how to handle
|
|
transmission of packets when the transmit buffer is full. The
|
|
value can be either 'iothread' or 'timer'.
|
|
<span class="since">Since 0.8.8 (QEMU and KVM only)</span><br/><br/>
|
|
|
|
If set to 'iothread', packet tx is all done in an iothread in
|
|
the bottom half of the driver (this option translates into
|
|
adding "tx=bh" to the qemu commandline -device virtio-net-pci
|
|
option).<br/><br/>
|
|
|
|
If set to 'timer', tx work is done in qemu, and if there is
|
|
more tx data than can be sent at the present time, a timer is
|
|
set before qemu moves on to do other things; when the timer
|
|
fires, another attempt is made to send more data.<br/><br/>
|
|
|
|
The resulting difference, according to the qemu developer who
|
|
added the option is: "bh makes tx more asynchronous and reduces
|
|
latency, but potentially causes more processor bandwidth
|
|
contention since the cpu doing the tx isn't necessarily the
|
|
cpu where the guest generated the packets."<br/><br/>
|
|
|
|
<b>In general you should leave this option alone, unless you
|
|
are very certain you know what you are doing.</b>
|
|
</dd>
|
|
<dt><code>ioeventfd</code></dt>
|
|
<dd>
|
|
This optional attribute allows users to set
|
|
<a href='https://patchwork.kernel.org/patch/43390/'>
|
|
domain I/O asynchronous handling</a> for interface device.
|
|
The default is left to the discretion of the hypervisor.
|
|
Accepted values are "on" and "off". Enabling this allows
|
|
qemu to execute VM while a separate thread handles I/O.
|
|
Typically guests experiencing high system CPU utilization
|
|
during I/O will benefit from this. On the other hand,
|
|
on overloaded host it could increase guest I/O latency.
|
|
<span class="since">Since 0.9.3 (QEMU and KVM only)</span><br/><br/>
|
|
|
|
<b>In general you should leave this option alone, unless you
|
|
are very certain you know what you are doing.</b>
|
|
</dd>
|
|
<dt><code>event_idx</code></dt>
|
|
<dd>
|
|
The <code>event_idx</code> attribute controls some aspects of
|
|
device event processing. The value can be either 'on' or 'off'
|
|
- if it is on, it will reduce the number of interrupts and
|
|
exits for the guest. The default is determined by QEMU;
|
|
usually if the feature is supported, default is on. In case
|
|
there is a situation where this behavior is suboptimal, this
|
|
attribute provides a way to force the feature off.
|
|
<span class="since">Since 0.9.5 (QEMU and KVM only)</span><br/><br/>
|
|
|
|
<b>In general you should leave this option alone, unless you
|
|
are very certain you know what you are doing.</b>
|
|
</dd>
|
|
<dt><code>queues</code></dt>
|
|
<dd>
|
|
The optional <code>queues</code> attribute controls the number of
|
|
queues to be used for the<a href="http://www.linux-kvm.org/page/Multiqueue">
|
|
Multiqueue virtio-net</a> feature. If the interface has <code><model
|
|
type='virtio'/></code>, multiple packet processing queues can be
|
|
created; each queue will potentially be handled by a different
|
|
processor, resulting in much higher throughput.
|
|
<span class="since">Since 1.0.6 (QEMU and KVM only)</span>
|
|
</dd>
|
|
<dt><code>host</code> offloading options</dt>
|
|
<dd>
|
|
The <code>csum</code>, <code>gso</code>, <code>tso4</code>,
|
|
<code>tso6</code>, <code>ecn</code> and <code>ufo</code>
|
|
attributes with possible values <code>on</code>
|
|
and <code>off</code> can be used to turn off host offloading options.
|
|
By default, the supported offloads are enabled by QEMU.
|
|
<span class="since">Since 1.2.9 (QEMU only)</span>
|
|
The <code>mrg_rxbuf</code> attribute can be used to control
|
|
mergeable rx buffers on the host side. Possible values are
|
|
<code>on</code> (default) and <code>off</code>.
|
|
<span class="since">Since 1.2.13 (QEMU only)</span>
|
|
</dd>
|
|
<dt><code>guest</code> offloading options</dt>
|
|
<dd>
|
|
The <code>csum</code>, <code>tso4</code>,
|
|
<code>tso6</code>, <code>ecn</code> and <code>ufo</code>
|
|
attributes with possible values <code>on</code>
|
|
and <code>off</code> can be used to turn off guest offloading options.
|
|
By default, the supported offloads are enabled by QEMU.
|
|
<span class="since">Since 1.2.9 (QEMU only)</span>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h5><a name="elementsBackendOptions">Setting network backend-specific options</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet1'/>
|
|
<model type='virtio'/>
|
|
<b><backend tap='/dev/net/tun' vhost='/dev/vhost-net'/></b>
|
|
<driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5'/>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
For tuning the backend of the network, the <code>backend</code> element
|
|
can be used. The <code>vhost</code> attribute can override the default vhost
|
|
device path (<code>/dev/vhost-net</code>) for devices with <code>virtio</code> model.
|
|
The <code>tap</code> attribute overrides the tun/tap device path (default:
|
|
<code>/dev/net/tun</code>) for network and bridge interfaces. This does not work
|
|
in session mode.
|
|
</p>
|
|
<h5><a name="elementsNICSTargetOverride">Overriding the target element</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<b><target dev='vnet1'/></b>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
If no target is specified, certain hypervisors will
|
|
automatically generate a name for the created tun device. This
|
|
name can be manually specified, however the name <i>must not
|
|
start with either 'vnet' or 'vif'</i>, which are prefixes
|
|
reserved by libvirt and certain hypervisors. Manually specified
|
|
targets using these prefixes will be ignored.
|
|
</p>
|
|
|
|
<p>
|
|
Note that for LXC containers, this defines the name of the interface
|
|
on the host side. <span class="since">Since 1.2.7</span>, to define
|
|
the name of the device on the guest side, the <code>guest</code>
|
|
element should be used, as in the following snippet:
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<b><guest dev='myeth'/></b>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h5><a name="elementsNICSBoot">Specifying boot order</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet1'/>
|
|
<b><boot order='1'/></b>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
For hypervisors which support this, you can set a specific NIC to
|
|
be used for network boot. The <code>order</code> attribute determines
|
|
the order in which devices will be tried during boot sequence. The
|
|
per-device <code>boot</code> elements cannot be used together with
|
|
general boot elements in
|
|
<a href="#elementsOSBIOS">BIOS bootloader</a> section.
|
|
<span class="since">Since 0.8.8</span>
|
|
</p>
|
|
|
|
<h5><a name="elementsNICSROM">Interface ROM BIOS configuration</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet1'/>
|
|
<b><rom bar='on' file='/etc/fake/boot.bin'/></b>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
For hypervisors which support this, you can change how a PCI Network
|
|
device's ROM is presented to the guest. The <code>bar</code>
|
|
attribute can be set to "on" or "off", and determines whether
|
|
or not the device's ROM will be visible in the guest's memory
|
|
map. (In PCI documentation, the "rombar" setting controls the
|
|
presence of the Base Address Register for the ROM). If no rom
|
|
bar is specified, the qemu default will be used (older
|
|
versions of qemu used a default of "off", while newer qemus
|
|
have a default of "on").
|
|
The optional <code>file</code> attribute is used to point to a
|
|
binary file to be presented to the guest as the device's ROM
|
|
BIOS. This can be useful to provide an alternative boot ROM for a
|
|
network device.
|
|
<span class="since">Since 0.9.10 (QEMU and KVM only)</span>.
|
|
</p>
|
|
<h5><a name="elementDomain">Setting up a network backend in a driver domain</a></h5>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
...
|
|
<interface type='bridge'>
|
|
<source bridge='br0'/>
|
|
<b><backenddomain name='netvm'/></b>
|
|
</interface>
|
|
...
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
The optional <code>backenddomain</code> element allows specifying a
|
|
backend domain (aka driver domain) for the interface. Use the
|
|
<code>name</code> attribute to specify the backend domain name. You
|
|
can use it to create a direct network link between domains (so data
|
|
will not go through host system). Use with type 'ethernet' to create
|
|
plain network link, or with type 'bridge' to connect to a bridge inside
|
|
the backend domain.
|
|
<span class="since">Since 1.2.13 (Xen only)</span>
|
|
</p>
|
|
|
|
<h5><a name="elementQoS">Quality of service</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet0'/>
|
|
<b><bandwidth>
|
|
<inbound average='1000' peak='5000' floor='200' burst='1024'/>
|
|
<outbound average='128' peak='256' burst='256'/>
|
|
</bandwidth></b>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
This part of interface XML provides setting quality of service. Incoming
|
|
and outgoing traffic can be shaped independently.
|
|
The <code>bandwidth</code> element and its child elements are described
|
|
in the <a href="formatnetwork.html#elementQoS">QoS</a> section of
|
|
the Network XML.
|
|
</p>
|
|
|
|
<h5><a name="elementVlanTag">Setting VLAN tag (on supported network types only)</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='bridge'>
|
|
<b><vlan></b>
|
|
<b><tag id='42'/></b>
|
|
<b></vlan></b>
|
|
<source bridge='ovsbr0'/>
|
|
<virtualport type='openvswitch'>
|
|
<parameters interfaceid='09b11c53-8b5c-4eeb-8f00-d84eaa0aaa4f'/>
|
|
</virtualport>
|
|
</interface>
|
|
<interface type='bridge'>
|
|
<b><vlan trunk='yes'></b>
|
|
<b><tag id='42'/></b>
|
|
<b><tag id='123' nativeMode='untagged'/></b>
|
|
<b></vlan></b>
|
|
...
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
If (and only if) the network connection used by the guest
|
|
supports vlan tagging transparent to the guest, an
|
|
optional <code><vlan></code> element can specify one or
|
|
more vlan tags to apply to the guest's network
|
|
traffic <span class="since">Since 0.10.0</span>. (openvswitch
|
|
and type='hostdev' SR-IOV interfaces do support transparent vlan
|
|
tagging of guest traffic; everything else, including standard
|
|
linux bridges and libvirt's own virtual networks, <b>do not</b>
|
|
support it. 802.1Qbh (vn-link) and 802.1Qbg (VEPA) switches
|
|
provide their own way (outside of libvirt) to tag guest traffic
|
|
onto specific vlans.) To allow for specification of multiple
|
|
tags (in the case of vlan trunking), a
|
|
subelement, <code><tag></code>, specifies which vlan tag
|
|
to use (for example: <code><tag id='42'/></code>. If an
|
|
interface has more than one <code><vlan></code> element
|
|
defined, it is assumed that the user wants to do VLAN trunking
|
|
using all the specified tags. In the case that vlan trunking
|
|
with a single tag is desired, the optional
|
|
attribute <code>trunk='yes'</code> can be added to the toplevel
|
|
vlan element.
|
|
</p>
|
|
|
|
<p>
|
|
For network connections using openvswitch it is possible to
|
|
configure the 'native-tagged' and 'native-untagged' vlan modes
|
|
<span class="since">Since 1.1.0.</span> This uses the optional
|
|
<code>nativeMode</code> attribute on the <code><tag></code>
|
|
element: <code>nativeMode</code> may be set to 'tagged' or
|
|
'untagged'. The id attribute of the element sets the native vlan.
|
|
</p>
|
|
|
|
<h5><a name="elementLink">Modifying virtual link state</a></h5>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet0'/>
|
|
<b><link state='down'/></b>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
This element provides means of setting state of the virtual network link.
|
|
Possible values for attribute <code>state</code> are <code>up</code> and
|
|
<code>down</code>. If <code>down</code> is specified as the value, the interface
|
|
behaves as if it had the network cable disconnected. Default behavior if this
|
|
element is unspecified is to have the link state <code>up</code>.
|
|
<span class="since">Since 0.9.5</span>
|
|
</p>
|
|
|
|
<h5><a name="ipconfig">IP configuration</a></h5>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet0'/>
|
|
<b><ip address='192.168.122.5' prefix='24'/></b>
|
|
<b><route family='ipv4' address='192.168.122.0' prefix='24' via='192.168.122.1'/></b>
|
|
<b><route family='ipv4' via='192.168.122.1'/></b>
|
|
</interface>
|
|
...
|
|
<hostdev mode='capabilities' type='net'>
|
|
<source>
|
|
<interface>eth0</interface>
|
|
</source>
|
|
<b><ip address='192.168.122.6' prefix='24'/></b>
|
|
<b><route family='ipv4' address='192.168.122.0' prefix='24' via='192.168.122.1'/></b>
|
|
<b><route family='ipv4' via='192.168.122.1'/></b>
|
|
</hostdev>
|
|
|
|
</devices>
|
|
...
|
|
</pre>
|
|
|
|
<p>
|
|
<span class="since">Since 1.2.12</span> the network devices and host devices
|
|
with network capabilities can be provided zero or more IP addresses to set
|
|
on the target device. Note that some hypervisors or network device types
|
|
will simply ignore them or only use the first one. The <code>family</code>
|
|
attribute can be set to either <code>ipv4</code> or <code>ipv6</code>, the
|
|
<code>address</code> attribute holds the IP address. The <code>prefix</code>
|
|
is not mandatory since some hypervisors do not handle it.
|
|
</p>
|
|
|
|
<p>
|
|
<span class="since">Since 1.2.12</span> route elements can also be added
|
|
to define the network routes to use for the network device. The attributes
|
|
of this element are described in the documentation for the <code>route</code>
|
|
element in <a href="formatnetwork.html#elementsStaticroute">network definitions</a>.
|
|
This is only used by the LXC driver.
|
|
</p>
|
|
|
|
<h5><a name="elementVhostuser">vhost-user interface</a></h5>
|
|
|
|
<p>
|
|
<span class="since">Since 1.2.7</span> the vhost-user enables the
|
|
communication between a QEMU virtual machine and other userspace process
|
|
using the Virtio transport protocol. A char dev (e.g. Unix socket) is used
|
|
for the control plane, while the data plane is based on shared memory.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='vhostuser'>
|
|
<mac address='52:54:00:3b:83:1a'/>
|
|
<source type='unix' path='/tmp/vhost.sock' mode='server'/>
|
|
<model type='virtio'/>
|
|
</interface>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
The <code><source></code> element has to be specified
|
|
along with the type of char device.
|
|
Currently, only type='unix' is supported, where the path (the
|
|
directory path of the socket) and mode attributes are required.
|
|
Both <code>mode='server'</code> and <code>mode='client'</code>
|
|
are supported.
|
|
vhost-user requires the virtio model type, thus the
|
|
<code><model></code> element is mandatory.
|
|
</p>
|
|
|
|
<h4><a name="elementsInput">Input devices</a></h4>
|
|
|
|
<p>
|
|
Input devices allow interaction with the graphical framebuffer
|
|
in the guest virtual machine. When enabling the framebuffer, an
|
|
input device is automatically provided. It may be possible to
|
|
add additional devices explicitly, for example,
|
|
to provide a graphics tablet for absolute cursor movement.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<input type='mouse' bus='usb'/>
|
|
<input type='keyboard' bus='usb'/>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>input</code></dt>
|
|
<dd>The <code>input</code> element has one mandatory attribute,
|
|
the <code>type</code> whose value can be 'mouse', 'tablet' or
|
|
(<span class="since">since 1.2.2</span>) 'keyboard'.
|
|
The tablet provides absolute cursor movement,
|
|
while the mouse uses relative movement. The optional
|
|
<code>bus</code> attribute can be used to refine the exact device type.
|
|
It takes values "xen" (paravirtualized), "ps2" and "usb".</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
The <code>input</code> element has an optional
|
|
sub-element <code><address></code> which can tie the
|
|
device to a particular PCI
|
|
slot, <a href="#elementsAddress">documented above</a>.
|
|
</p>
|
|
|
|
<h4><a name="elementsHub">Hub devices</a></h4>
|
|
|
|
<p>
|
|
A hub is a device that expands a single port into several so
|
|
that there are more ports available to connect devices to a host
|
|
system.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<hub type='usb'/>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>hub</code></dt>
|
|
<dd>The <code>hub</code> element has one mandatory attribute,
|
|
the <code>type</code> whose value can only be 'usb'.</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
The <code>hub</code> element has an optional
|
|
sub-element <code><address></code>
|
|
with <code>type='usb'</code>which can tie the device to a
|
|
particular controller, <a href="#elementsAddress">documented
|
|
above</a>.
|
|
</p>
|
|
|
|
<h4><a name="elementsGraphics">Graphical framebuffers</a></h4>
|
|
|
|
<p>
|
|
A graphics device allows for graphical interaction with the
|
|
guest OS. A guest will typically have either a framebuffer
|
|
or a text console configured to allow interaction with the
|
|
admin.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<graphics type='sdl' display=':0.0'/>
|
|
<graphics type='vnc' port='5904' sharePolicy='allow-exclusive'>
|
|
<listen type='address' address='1.2.3.4'/>
|
|
</graphics>
|
|
<graphics type='rdp' autoport='yes' multiUser='yes' />
|
|
<graphics type='desktop' fullscreen='yes'/>
|
|
<graphics type='spice'>
|
|
<listen type='network' network='rednet'/>
|
|
</graphics>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>graphics</code></dt>
|
|
<dd>The <code>graphics</code> element has a mandatory <code>type</code>
|
|
attribute which takes the value "sdl", "vnc", "rdp" or "desktop":
|
|
<dl>
|
|
<dt><code>"sdl"</code></dt>
|
|
<dd>
|
|
This displays a window on the host desktop, it can take 3
|
|
optional arguments: a <code>display</code> attribute for
|
|
the display to use, an <code>xauth</code> attribute for
|
|
the authentication identifier, and an
|
|
optional <code>fullscreen</code> attribute accepting
|
|
values 'yes' or 'no'.
|
|
</dd>
|
|
<dt><code>"vnc"</code></dt>
|
|
<dd>
|
|
Starts a VNC server. The <code>port</code> attribute
|
|
specifies the TCP port number (with -1 as legacy syntax
|
|
indicating that it should be
|
|
auto-allocated). The <code>autoport</code> attribute is
|
|
the new preferred syntax for indicating autoallocation of
|
|
the TCP port to use. The <code>listen</code> attribute is
|
|
an IP address for the server to listen
|
|
on. The <code>passwd</code> attribute provides a VNC
|
|
password in clear text. The <code>keymap</code> attribute
|
|
specifies the keymap to use. It is possible to set a limit
|
|
on the validity of the password be giving an
|
|
timestamp <code>passwdValidTo='2010-04-09T15:51:00'</code>
|
|
assumed to be in UTC. The <code>connected</code> attribute
|
|
allows control of connected client during password changes.
|
|
VNC accepts <code>keep</code> value only.
|
|
<span class="since">since 0.9.3</span>
|
|
NB, this may not be supported by all hypervisors.<br/>
|
|
The optional <code>sharePolicy</code> attribute specifies vnc server
|
|
display sharing policy. "allow-exclusive" allows clients to ask
|
|
for exclusive access by dropping other connections. Connecting
|
|
multiple clients in parallel requires all clients asking for a
|
|
shared session (vncviewer: -Shared switch). This is the default
|
|
value. "force-shared" disables exclusive client access, every
|
|
connection has to specify -Shared switch for vncviewer. "ignore"
|
|
welcomes every connection unconditionally
|
|
<span class="since">since 1.0.6</span>. <br/> <br/>
|
|
Rather than using listen/port, QEMU supports a
|
|
<code>socket</code> attribute for listening on a unix
|
|
domain socket path.<span class="since">Since 0.8.8</span>
|
|
|
|
For VNC WebSocket functionality, <code>websocket</code>
|
|
attribute may be used to specify port to listen on (with
|
|
-1 meaning auto-allocation and <code>autoport</code>
|
|
having no effect due to security reasons).
|
|
<span class="since">Since 1.0.6</span>
|
|
</dd>
|
|
<dt><code>"spice"</code></dt>
|
|
<dd>
|
|
<p>
|
|
Starts a SPICE server. The <code>port</code> attribute
|
|
specifies the TCP port number (with -1 as legacy syntax
|
|
indicating that it should be auto-allocated),
|
|
while <code>tlsPort</code> gives an alternative secure
|
|
port number. The <code>autoport</code> attribute is the
|
|
new preferred syntax for indicating autoallocation of
|
|
needed port numbers. The <code>listen</code> attribute is
|
|
an IP address for the server to listen
|
|
on. The <code>passwd</code> attribute provides a SPICE
|
|
password in clear text. The <code>keymap</code>
|
|
attribute specifies the keymap to use. It is possible to
|
|
set a limit on the validity of the password be giving an
|
|
timestamp <code>passwdValidTo='2010-04-09T15:51:00'</code>
|
|
assumed to be in UTC. The <code>connected</code> attribute
|
|
allows control of connected client during password changes.
|
|
SPICE accepts <code>keep</code> to keep client connected,
|
|
<code>disconnect</code> to disconnect client and
|
|
<code>fail</code> to fail changing password.
|
|
<span class="since">Since 0.9.3</span>
|
|
NB, this may not be supported by all hypervisors.
|
|
<span class="since">"spice" since 0.8.6</span>.
|
|
The <code>defaultMode</code> attribute sets the default channel
|
|
security policy, valid values are <code>secure</code>,
|
|
<code>insecure</code> and the default <code>any</code>
|
|
(which is secure if possible, but falls back to insecure
|
|
rather than erroring out if no secure path is
|
|
available). <span class="since">"defaultMode" since
|
|
0.9.12</span>.
|
|
</p>
|
|
<p>
|
|
When SPICE has both a normal and TLS secured TCP port
|
|
configured, it can be desirable to restrict what
|
|
channels can be run on each port. This is achieved by
|
|
adding one or more <channel> elements inside the
|
|
main <graphics> element and setting the <code>mode</code>
|
|
attribute to either <code>secure</code> or <code>insecure</code>.
|
|
Setting the mode attribute overrides the default value as set
|
|
by the <code>defaultMode</code> attribute. (Note that specifying
|
|
<code>any</code> as mode discards the entry as the channel would
|
|
inherit the default mode anyways)
|
|
Valid channel names
|
|
include <code>main</code>, <code>display</code>,
|
|
<code>inputs</code>, <code>cursor</code>,
|
|
<code>playback</code>, <code>record</code>
|
|
(all <span class="since"> since 0.8.6</span>);
|
|
<code>smartcard</code> (<span class="since">since
|
|
0.8.8</span>); and <code>usbredir</code>
|
|
(<span class="since">since 0.9.12</span>).
|
|
</p>
|
|
<pre>
|
|
<graphics type='spice' port='-1' tlsPort='-1' autoport='yes'>
|
|
<channel name='main' mode='secure'/>
|
|
<channel name='record' mode='insecure'/>
|
|
<image compression='auto_glz'/>
|
|
<streaming mode='filter'/>
|
|
<clipboard copypaste='no'/>
|
|
<mouse mode='client'/>
|
|
<filetransfer enable='no'/>
|
|
</graphics></pre>
|
|
<p>
|
|
Spice supports variable compression settings for audio,
|
|
images and streaming, <span class="since">since
|
|
0.9.1</span>. These settings are accessible via
|
|
the <code>compression</code> attribute in all following
|
|
elements: <code>image</code> to set image compression
|
|
(accepts <code>auto_glz</code>, <code>auto_lz</code>,
|
|
<code>quic</code>, <code>glz</code>, <code>lz</code>,
|
|
<code>off</code>), <code>jpeg</code> for JPEG
|
|
compression for images over wan
|
|
(accepts <code>auto</code>, <code>never</code>,
|
|
<code>always</code>), <code>zlib</code> for configuring
|
|
wan image compression (accepts <code>auto</code>,
|
|
<code>never</code>, <code>always</code>)
|
|
and <code>playback</code> for enabling audio stream
|
|
compression (accepts <code>on</code> or <code>off</code>).
|
|
</p>
|
|
<p>
|
|
Streaming mode is set by the <code>streaming</code>
|
|
element, settings its <code>mode</code> attribute to one
|
|
of <code>filter</code>, <code>all</code>
|
|
or <code>off</code>, <span class="since">since 0.9.2</span>.
|
|
</p>
|
|
<p>
|
|
Copy & Paste functionality (via Spice agent) is set
|
|
by the <code>clipboard</code> element. It is enabled by
|
|
default, and can be disabled by setting
|
|
the <code>copypaste</code> property
|
|
to <code>no</code>, <span class="since">since
|
|
0.9.3</span>.
|
|
</p>
|
|
<p>
|
|
Mouse mode is set by the <code>mouse</code> element,
|
|
setting its <code>mode</code> attribute to one of
|
|
<code>server</code> or <code>client</code> ,
|
|
<span class="since">since 0.9.11</span>. If no mode is
|
|
specified, the qemu default will be used (client mode).
|
|
</p>
|
|
<p>
|
|
File transfer functionality (via Spice agent) is set using the
|
|
<code>filetransfer</code> element.
|
|
It is enabled by default, and can be disabled by setting the
|
|
<code>enable</code> property to <code>no</code> ,
|
|
since <span class="since">since 1.2.2</span>.
|
|
</p>
|
|
</dd>
|
|
<dt><code>"rdp"</code></dt>
|
|
<dd>
|
|
Starts a RDP server. The <code>port</code> attribute
|
|
specifies the TCP port number (with -1 as legacy syntax
|
|
indicating that it should be
|
|
auto-allocated). The <code>autoport</code> attribute is
|
|
the new preferred syntax for indicating autoallocation of
|
|
the TCP port to use. The <code>replaceUser</code>
|
|
attribute is a boolean deciding whether multiple
|
|
simultaneous connections to the VM are permitted.
|
|
The <code>multiUser</code> attribute is a boolean deciding
|
|
whether the existing connection must be dropped and a new
|
|
connection must be established by the VRDP server, when a
|
|
new client connects in single connection mode.
|
|
</dd>
|
|
<dt><code>"desktop"</code></dt>
|
|
<dd>
|
|
This value is reserved for VirtualBox domains for the
|
|
moment. It displays a window on the host desktop,
|
|
similarly to "sdl", but using the VirtualBox viewer. Just
|
|
like "sdl", it accepts the optional
|
|
attributes <code>display</code>
|
|
and <code>fullscreen</code>.
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
Rather than putting the address information used to set up the
|
|
listening socket for graphics types <code>vnc</code>
|
|
and <code>spice</code> in
|
|
the <code><graphics></code> <code>listen</code> attribute,
|
|
a separate subelement of <code><graphics></code>,
|
|
called <code><listen></code> can be specified (see the
|
|
examples above)<span class="since">since
|
|
0.9.4</span>. <code><listen></code> accepts the following
|
|
attributes:
|
|
</p>
|
|
<dl>
|
|
<dt><code>type</code></dt>
|
|
<dd>Set to either <code>address</code>
|
|
or <code>network</code>. This tells whether this listen
|
|
element is specifying the address to be used directly, or by
|
|
naming a network (which will then be used to determine an
|
|
appropriate address for listening).
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dt><code>address</code></dt>
|
|
<dd>if <code>type='address'</code>, the <code>address</code>
|
|
attribute will contain either an IP address or hostname (which
|
|
will be resolved to an IP address via a DNS query) to listen
|
|
on. In the "live" XML of a running domain, this attribute will
|
|
be set to the IP address used for listening, even
|
|
if <code>type='network'</code>.
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dt><code>network</code></dt>
|
|
<dd>if <code>type='network'</code>, the <code>network</code>
|
|
attribute will contain the name of a network in libvirt's list
|
|
of configured networks. The named network configuration will
|
|
be examined to determine an appropriate listen address. For
|
|
example, if the network has an IPv4 address in its
|
|
configuration (e.g. if it has a forward type
|
|
of <code>route</code>, <code>nat</code>, or no forward type
|
|
(isolated)), the first IPv4 address listed in the network's
|
|
configuration will be used. If the network is describing a
|
|
host bridge, the first IPv4 address associated with that
|
|
bridge device will be used, and if the network is describing
|
|
one of the 'direct' (macvtap) modes, the first IPv4 address of
|
|
the first forward dev will be used.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsVideo">Video devices</a></h4>
|
|
<p>
|
|
A video device.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<video>
|
|
<model type='vga' vram='16384' heads='1'>
|
|
<acceleration accel3d='yes' accel2d='yes'/>
|
|
</model>
|
|
</video>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>video</code></dt>
|
|
<dd>
|
|
<p>
|
|
The <code>video</code> element is the container for describing
|
|
video devices. For backwards compatibility, if no <code>video</code>
|
|
is set but there is a <code>graphics</code> in domain xml, then
|
|
libvirt will add a default <code>video</code> according to the guest
|
|
type.
|
|
</p>
|
|
<p>
|
|
For a guest of type "kvm", the default <code>video</code> is:
|
|
<code>type</code> with value "cirrus", <code>vram</code> with value
|
|
"16384" and <code>heads</code> with value "1". By default, the first
|
|
video device in domain xml is the primary one, but the optional
|
|
attribute <code>primary</code> (<span class="since">since 1.0.2</span>)
|
|
with value 'yes' can be used to mark the primary in cases of multiple
|
|
video device. The non-primary must be type of "qxl".
|
|
</p>
|
|
</dd>
|
|
|
|
<dt><code>model</code></dt>
|
|
<dd>
|
|
<p>
|
|
The <code>model</code> element has a mandatory <code>type</code>
|
|
attribute which takes the value "vga", "cirrus", "vmvga", "xen",
|
|
"vbox", or "qxl" (<span class="since">since 0.8.6</span>) depending
|
|
on the hypervisor features available.
|
|
</p>
|
|
<p>
|
|
You can provide the amount of video memory in kibibytes (blocks of
|
|
1024 bytes) using <code>vram</code>. This is supported only for guest
|
|
type of "libxl", "parallels", "qemu", "vbox", "vmx" and "xen". If no
|
|
value is provided the default is used. If the size is not a power of
|
|
two it will be rounded to closest one.
|
|
</p>
|
|
<p>
|
|
The number of screen can be set using <code>heads</code>. This is
|
|
supported only for guests type of "parallels", "kvm", "vbox" and "vmx".
|
|
</p>
|
|
<p>
|
|
For guest type of kvm the optional attribute <code>ram</code>
|
|
(<span class="since">since 1.0.2</span>) is allowed for "qxl" type
|
|
only and specifies the size of the primary bar, while the optional
|
|
attribute <code>vram</code> specifies the secondary bar size.
|
|
If "ram" or "vram" are not supplied a default value is used. The ram
|
|
should also be rounded to power of two as vram. There is also optional
|
|
attribute <code>vgamem</code> (<span class="since">since 1.2.11 (QEMU
|
|
only)</span>) to set the size of VGA framebuffer for fallback mode of
|
|
QXL device.
|
|
</p>
|
|
</dd>
|
|
|
|
<dt><code>acceleration</code></dt>
|
|
<dd>
|
|
If acceleration should be enabled (if supported) using the
|
|
<code>accel3d</code> and <code>accel2d</code> attributes in the
|
|
<code>acceleration</code> element.
|
|
</dd>
|
|
|
|
<dt><code>address</code></dt>
|
|
<dd>
|
|
The optional <code>address</code> sub-element can be used to
|
|
tie the video device to a particular PCI slot.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsConsole">Consoles, serial, parallel & channel devices</a></h4>
|
|
|
|
<p>
|
|
A character device provides a way to interact with the virtual machine.
|
|
Paravirtualized consoles, serial ports, parallel ports and channels are
|
|
all classed as character devices and so represented using the same syntax.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<parallel type='pty'>
|
|
<source path='/dev/pts/2'/>
|
|
<target port='0'/>
|
|
</parallel>
|
|
<serial type='pty'>
|
|
<source path='/dev/pts/3'/>
|
|
<target port='0'/>
|
|
</serial>
|
|
<serial type='file'>
|
|
<source path='/tmp/file'>
|
|
<seclabel model='dac' relabel='no'/>
|
|
</source>
|
|
<target port='0'/>
|
|
</serial>
|
|
<console type='pty'>
|
|
<source path='/dev/pts/4'/>
|
|
<target port='0'/>
|
|
</console>
|
|
<channel type='unix'>
|
|
<source mode='bind' path='/tmp/guestfwd'/>
|
|
<target type='guestfwd' address='10.0.2.1' port='4600'/>
|
|
</channel>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
In each of these directives, the top-level element name (parallel, serial,
|
|
console, channel) describes how the device is presented to the guest. The
|
|
guest interface is configured by the <code>target</code> element.
|
|
</p>
|
|
|
|
<p>
|
|
The interface presented to the host is given in the <code>type</code>
|
|
attribute of the top-level element. The host interface is
|
|
configured by the <code>source</code> element.
|
|
</p>
|
|
|
|
<p>
|
|
The <code>source</code> element may contain an optional
|
|
<code>seclabel</code> to override the way that labelling
|
|
is done on the socket path. If this element is not present,
|
|
the <a href="#seclabel">security label is inherited from
|
|
the per-domain setting</a>.
|
|
</p>
|
|
|
|
<p>
|
|
Each character device element has an optional
|
|
sub-element <code><address></code> which can tie the
|
|
device to a
|
|
particular <a href="#elementsControllers">controller</a> or PCI
|
|
slot.
|
|
</p>
|
|
|
|
<h5><a name="elementsCharGuestInterface">Guest interface</a></h5>
|
|
|
|
<p>
|
|
A character device presents itself to the guest as one of the following
|
|
types.
|
|
</p>
|
|
|
|
<h6><a name="elementCharParallel">Parallel port</a></h6>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<parallel type='pty'>
|
|
<source path='/dev/pts/2'/>
|
|
<target port='0'/>
|
|
</parallel>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
<code>target</code> can have a <code>port</code> attribute, which
|
|
specifies the port number. Ports are numbered starting from 0. There are
|
|
usually 0, 1 or 2 parallel ports.
|
|
</p>
|
|
|
|
<h6><a name="elementCharSerial">Serial port</a></h6>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type='pty'>
|
|
<source path='/dev/pts/3'/>
|
|
<target port='0'/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
<code>target</code> can have a <code>port</code> attribute, which
|
|
specifies the port number. Ports are numbered starting from 0. There are
|
|
usually 0, 1 or 2 serial ports. There is also an optional
|
|
<code>type</code> attribute <span class="since">since 1.0.2</span>
|
|
which has two choices for its value, one is <code>isa-serial</code>,
|
|
the other is <code>usb-serial</code>. If <code>type</code> is missing,
|
|
<code>isa-serial</code> will be used by default. For <code>usb-serial</code>
|
|
an optional sub-element <code><address></code> with
|
|
<code>type='usb'</code> can tie the device to a particular controller,
|
|
<a href="#elementsAddress">documented above</a>.
|
|
</p>
|
|
|
|
<h6><a name="elementCharConsole">Console</a></h6>
|
|
|
|
<p>
|
|
The console element is used to represent interactive consoles. Depending
|
|
on the type of guest in use, the consoles might be paravirtualized devices,
|
|
or they might be a clone of a serial device, according to the following
|
|
rules:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>If no <code>targetType</code> attribute is set, then the default
|
|
device type is according to the hypervisor's rules. The default
|
|
type will be added when re-querying the XML fed into libvirt.
|
|
For fully virtualized guests, the default device type will usually
|
|
be a serial port.</li>
|
|
<li>If the <code>targetType</code> attribute is <code>serial</code>,
|
|
then if no <code><serial></code> element exists, the console
|
|
element will be copied to the serial element. If a <code><serial></code>
|
|
element does already exist, the console element will be ignored.</li>
|
|
<li>If the <code>targetType</code> attribute is not <code>serial</code>,
|
|
it will be treated normally.</li>
|
|
<li>Only the first <code>console</code> element may use a <code>targetType</code>
|
|
of <code>serial</code>. Secondary consoles must all be paravirtualized.
|
|
</li>
|
|
<li>On s390, the <code>console</code> element may use a
|
|
<code>targetType</code> of <code>sclp</code> or <code>sclplm</code>
|
|
(line mode). SCLP is the native console type for s390. There's no
|
|
controller associated to SCLP consoles.
|
|
<span class="since">Since 1.0.2</span>
|
|
</li>
|
|
</ul>
|
|
|
|
<p>
|
|
A virtio console device is exposed in the
|
|
guest as /dev/hvc[0-7] (for more information, see
|
|
<a href="http://fedoraproject.org/wiki/Features/VirtioSerial">http://fedoraproject.org/wiki/Features/VirtioSerial</a>)
|
|
<span class="since">Since 0.8.3</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<console type='pty'>
|
|
<source path='/dev/pts/4'/>
|
|
<target port='0'/>
|
|
</console>
|
|
|
|
<!-- KVM virtio console -->
|
|
<console type='pty'>
|
|
<source path='/dev/pts/5'/>
|
|
<target type='virtio' port='0'/>
|
|
</console>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<!-- KVM s390 sclp console -->
|
|
<console type='pty'>
|
|
<source path='/dev/pts/1'/>
|
|
<target type='sclp' port='0'/>
|
|
</console>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
If the console is presented as a serial port, the <code>target</code>
|
|
element has the same attributes as for a serial port. There is usually
|
|
only 1 console.
|
|
</p>
|
|
|
|
<h6><a name="elementCharChannel">Channel</a></h6>
|
|
|
|
<p>
|
|
This represents a private communication channel between the host and the
|
|
guest.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<channel type='unix'>
|
|
<source mode='bind' path='/tmp/guestfwd'/>
|
|
<target type='guestfwd' address='10.0.2.1' port='4600'/>
|
|
</channel>
|
|
|
|
<!-- KVM virtio channel -->
|
|
<channel type='pty'>
|
|
<target type='virtio' name='arbitrary.virtio.serial.port.name'/>
|
|
</channel>
|
|
<channel type='unix'>
|
|
<source mode='bind' path='/var/lib/libvirt/qemu/f16x86_64.agent'/>
|
|
<target type='virtio' name='org.qemu.guest_agent.0' state='connected'/>
|
|
</channel>
|
|
<channel type='spicevmc'>
|
|
<target type='virtio' name='com.redhat.spice.0'/>
|
|
</channel>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
This can be implemented in a variety of ways. The specific type of
|
|
channel is given in the <code>type</code> attribute of the
|
|
<code>target</code> element. Different channel types have different
|
|
<code>target</code> attributes.
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>guestfwd</code></dt>
|
|
<dd>TCP traffic sent by the guest to a given IP address and port is
|
|
forwarded to the channel device on the host. The <code>target</code>
|
|
element must have <code>address</code> and <code>port</code> attributes.
|
|
<span class="since">Since 0.7.3</span></dd>
|
|
|
|
<dt><code>virtio</code></dt>
|
|
<dd>Paravirtualized virtio channel. Channel is exposed in the guest under
|
|
/dev/vport*, and if the optional element <code>name</code> is specified,
|
|
/dev/virtio-ports/$name (for more info, please see
|
|
<a href="http://fedoraproject.org/wiki/Features/VirtioSerial">http://fedoraproject.org/wiki/Features/VirtioSerial</a>). The
|
|
optional element <code>address</code> can tie the channel to a
|
|
particular <code>type='virtio-serial'</code>
|
|
controller, <a href="#elementsAddress">documented above</a>.
|
|
With qemu, if <code>name</code> is "org.qemu.guest_agent.0",
|
|
then libvirt can interact with a guest agent installed in the
|
|
guest, for actions such as guest shutdown or file system quiescing.
|
|
<span class="since">Since 0.7.7, guest agent interaction
|
|
since 0.9.10</span> Moreover, <span class="since">since 1.0.6</span>
|
|
it is possible to have source path auto generated for virtio unix channels.
|
|
This is very useful in case of a qemu guest agent, where users don't
|
|
usually care about the source path since it's libvirt who talks to
|
|
the guest agent. In case users want to utilize this feature, they should
|
|
leave <code><source></code> element out. <span class="since">Since
|
|
1.2.11</span> the active XML for a virtio channel may contain an optional
|
|
<code>state</code> attribute that reflects whether a process in the
|
|
guest is active on the channel. This is an output-only attribute.
|
|
Possible values for the <code>state</code> attribute are
|
|
<code>connected</code> and <code>disconnected</code>.
|
|
</dd>
|
|
<dt><code>spicevmc</code></dt>
|
|
<dd>Paravirtualized SPICE channel. The domain must also have a
|
|
SPICE server as a <a href="#elementsGraphics">graphics
|
|
device</a>, at which point the host piggy-backs messages
|
|
across the <code>main</code> channel. The <code>target</code>
|
|
element must be present, with
|
|
attribute <code>type='virtio'</code>; an optional
|
|
attribute <code>name</code> controls how the guest will have
|
|
access to the channel, and defaults
|
|
to <code>name='com.redhat.spice.0'</code>. The
|
|
optional <code>address</code> element can tie the channel to a
|
|
particular <code>type='virtio-serial'</code> controller.
|
|
<span class="since">Since 0.8.8</span></dd>
|
|
</dl>
|
|
|
|
<h5><a name="elementsCharHostInterface">Host interface</a></h5>
|
|
|
|
<p>
|
|
A character device presents itself to the host as one of the following
|
|
types.
|
|
</p>
|
|
|
|
<h6><a name="elementsCharSTDIO">Domain logfile</a></h6>
|
|
|
|
<p>
|
|
This disables all input on the character device, and sends output
|
|
into the virtual machine's logfile
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<console type='stdio'>
|
|
<target port='1'/>
|
|
</console>
|
|
</devices>
|
|
...</pre>
|
|
|
|
|
|
<h6><a name="elementsCharFle">Device logfile</a></h6>
|
|
|
|
<p>
|
|
A file is opened and all data sent to the character
|
|
device is written to the file.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="file">
|
|
<source path="/var/log/vm/vm-serial.log"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsCharVC">Virtual console</a></h6>
|
|
|
|
<p>
|
|
Connects the character device to the graphical framebuffer in
|
|
a virtual console. This is typically accessed via a special
|
|
hotkey sequence such as "ctrl+alt+3"
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type='vc'>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsCharNull">Null device</a></h6>
|
|
|
|
<p>
|
|
Connects the character device to the void. No data is ever
|
|
provided to the input. All data written is discarded.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type='null'>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsCharPTY">Pseudo TTY</a></h6>
|
|
|
|
<p>
|
|
A Pseudo TTY is allocated using /dev/ptmx. A suitable client
|
|
such as 'virsh console' can connect to interact with the
|
|
serial port locally.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="pty">
|
|
<source path="/dev/pts/3"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
NB special case if <console type='pty'>, then the TTY
|
|
path is also duplicated as an attribute tty='/dev/pts/3'
|
|
on the top level <console> tag. This provides compat
|
|
with existing syntax for <console> tags.
|
|
</p>
|
|
|
|
<h6><a name="elementsCharHost">Host device proxy</a></h6>
|
|
|
|
<p>
|
|
The character device is passed through to the underlying
|
|
physical character device. The device types must match,
|
|
eg the emulated serial port should only be connected to
|
|
a host serial port - don't connect a serial port to a parallel
|
|
port.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="dev">
|
|
<source path="/dev/ttyS0"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsCharPipe">Named pipe</a></h6>
|
|
|
|
<p>
|
|
The character device writes output to a named pipe. See pipe(7) for
|
|
more info.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="pipe">
|
|
<source path="/tmp/mypipe"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsCharTCP">TCP client/server</a></h6>
|
|
|
|
<p>
|
|
The character device acts as a TCP client connecting to a
|
|
remote server.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="tcp">
|
|
<source mode="connect" host="0.0.0.0" service="2445"/>
|
|
<protocol type="raw"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
Or as a TCP server waiting for a client connection.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="tcp">
|
|
<source mode="bind" host="127.0.0.1" service="2445"/>
|
|
<protocol type="raw"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
Alternatively you can use <code>telnet</code> instead
|
|
of <code>raw</code> TCP. <span class="since">Since 0.8.5</span>
|
|
you can also use <code>telnets</code>
|
|
(secure telnet) and <code>tls</code>.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="tcp">
|
|
<source mode="connect" host="0.0.0.0" service="2445"/>
|
|
<protocol type="telnet"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
...
|
|
<serial type="tcp">
|
|
<source mode="bind" host="127.0.0.1" service="2445"/>
|
|
<protocol type="telnet"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsCharUDP">UDP network console</a></h6>
|
|
|
|
<p>
|
|
The character device acts as a UDP netconsole service,
|
|
sending and receiving packets. This is a lossy service.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="udp">
|
|
<source mode="bind" host="0.0.0.0" service="2445"/>
|
|
<source mode="connect" host="0.0.0.0" service="2445"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsCharUNIX">UNIX domain socket client/server</a></h6>
|
|
|
|
<p>
|
|
The character device acts as a UNIX domain socket server,
|
|
accepting connections from local clients.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="unix">
|
|
<source mode="bind" path="/tmp/foo"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsCharSpiceport">Spice channel</a></h6>
|
|
|
|
<p>
|
|
The character device is accessible through spice connection
|
|
under a channel name specified in the <code>channel</code>
|
|
attribute. <span class="since">Since 1.2.2</span>
|
|
</p>
|
|
<p>
|
|
Note: depending on the hypervisor, spiceports might (or might not)
|
|
be enabled on domains with or without <a href="#elementsGraphics">spice
|
|
graphics</a>.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="spiceport">
|
|
<source channel="org.qemu.console.serial.0"/>
|
|
<target port="1"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<h6><a name="elementsNmdm">Nmdm device</a></h6>
|
|
|
|
<p>
|
|
The nmdm device driver, available on FreeBSD, provides two
|
|
tty devices connected together by a virtual null modem cable.
|
|
<span class="since">Since 1.2.4</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<serial type="nmdm">
|
|
<source master="/dev/nmdm0A" slave="/dev/nmdm0B"/>
|
|
</serial>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
The <code>source</code> element has these attributes:
|
|
</p>
|
|
|
|
<dl>
|
|
<dt><code>master</code></dt>
|
|
<dd>Master device of the pair, that is passed to the hypervisor.</dd>
|
|
|
|
<dt><code>slave</code></dt>
|
|
<dd>Slave device of the pair, that is passed to the clients for connection
|
|
to the guest console.</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsSound">Sound devices</a></h4>
|
|
|
|
<p>
|
|
A virtual sound card can be attached to the host via the
|
|
<code>sound</code> element. <span class="since">Since 0.4.3</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<sound model='es1370'/>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>sound</code></dt>
|
|
<dd>
|
|
The <code>sound</code> element has one mandatory attribute,
|
|
<code>model</code>, which specifies what real sound device is emulated.
|
|
Valid values are specific to the underlying hypervisor, though typical
|
|
choices are 'es1370', 'sb16', 'ac97', 'ich6' and 'usb'.
|
|
(<span class="since">
|
|
'ac97' only since 0.6.0, 'ich6' only since 0.8.8,
|
|
'usb' only since 1.2.7</span>)
|
|
</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
<span class="since">Since 0.9.13</span>, a sound element
|
|
with <code>ich6</code> model can have optional
|
|
sub-elements <code><codec></code> to attach various audio
|
|
codecs to the audio device. If not specified, a default codec
|
|
will be attached to allow playback and recording. Valid values
|
|
are 'duplex' (advertise a line-in and a line-out) and 'micro'
|
|
(advertise a speaker and a microphone).
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<sound model='ich6'>
|
|
<codec type='micro'/>
|
|
</sound>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
Each <code>sound</code> element has an optional
|
|
sub-element <code><address></code> which can tie the
|
|
device to a particular PCI
|
|
slot, <a href="#elementsAddress">documented above</a>.
|
|
</p>
|
|
|
|
<h4><a name="elementsWatchdog">Watchdog device</a></h4>
|
|
|
|
<p>
|
|
A virtual hardware watchdog device can be added to the guest via
|
|
the <code>watchdog</code> element.
|
|
<span class="since">Since 0.7.3, QEMU and KVM only</span>
|
|
</p>
|
|
|
|
<p>
|
|
The watchdog device requires an additional driver and management
|
|
daemon in the guest. Just enabling the watchdog in the libvirt
|
|
configuration does not do anything useful on its own.
|
|
</p>
|
|
|
|
<p>
|
|
Currently libvirt does not support notification when the
|
|
watchdog fires. This feature is planned for a future version of
|
|
libvirt.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<watchdog model='i6300esb'/>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<watchdog model='i6300esb' action='poweroff'/>
|
|
</devices>
|
|
</domain></pre>
|
|
|
|
<dl>
|
|
<dt><code>model</code></dt>
|
|
<dd>
|
|
<p>
|
|
The required <code>model</code> attribute specifies what real
|
|
watchdog device is emulated. Valid values are specific to the
|
|
underlying hypervisor.
|
|
</p>
|
|
<p>
|
|
QEMU and KVM support:
|
|
</p>
|
|
<ul>
|
|
<li> 'i6300esb' — the recommended device,
|
|
emulating a PCI Intel 6300ESB </li>
|
|
<li> 'ib700' — emulating an ISA iBase IB700 </li>
|
|
</ul>
|
|
</dd>
|
|
<dt><code>action</code></dt>
|
|
<dd>
|
|
<p>
|
|
The optional <code>action</code> attribute describes what
|
|
action to take when the watchdog expires. Valid values are
|
|
specific to the underlying hypervisor.
|
|
</p>
|
|
<p>
|
|
QEMU and KVM support:
|
|
</p>
|
|
<ul>
|
|
<li>'reset' — default, forcefully reset the guest</li>
|
|
<li>'shutdown' — gracefully shutdown the guest
|
|
(not recommended) </li>
|
|
<li>'poweroff' — forcefully power off the guest</li>
|
|
<li>'pause' — pause the guest</li>
|
|
<li>'none' — do nothing</li>
|
|
<li>'dump' — automatically dump the guest
|
|
<span class="since">Since 0.8.7</span></li>
|
|
</ul>
|
|
<p>
|
|
Note 1: the 'shutdown' action requires that the guest
|
|
is responsive to ACPI signals. In the sort of situations
|
|
where the watchdog has expired, guests are usually unable
|
|
to respond to ACPI signals. Therefore using 'shutdown'
|
|
is not recommended.
|
|
</p>
|
|
<p>
|
|
Note 2: the directory to save dump files can be configured
|
|
by <code>auto_dump_path</code> in file /etc/libvirt/qemu.conf.
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsMemBalloon">Memory balloon device</a></h4>
|
|
|
|
<p>
|
|
A virtual memory balloon device is added to all Xen and KVM/QEMU
|
|
guests. It will be seen as <code>memballoon</code> element.
|
|
It will be automatically added when appropriate, so there is no
|
|
need to explicitly add this element in the guest XML unless a
|
|
specific PCI slot needs to be assigned.
|
|
<span class="since">Since 0.8.3, Xen, QEMU and KVM only</span>
|
|
Additionally, <span class="since">since 0.8.4</span>, if the
|
|
memballoon device needs to be explicitly disabled,
|
|
<code>model='none'</code> may be used.
|
|
</p>
|
|
|
|
<p>
|
|
Example: automatically added device with KVM
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<memballoon model='virtio'/>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
Example: manually added device with static PCI slot 2 requested
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<memballoon model='virtio'>
|
|
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
|
|
<stats period='10'/>
|
|
</memballoon>
|
|
</devices>
|
|
</domain></pre>
|
|
|
|
<dl>
|
|
<dt><code>model</code></dt>
|
|
<dd>
|
|
<p>
|
|
The required <code>model</code> attribute specifies what type
|
|
of balloon device is provided. Valid values are specific to
|
|
the virtualization platform
|
|
</p>
|
|
<ul>
|
|
<li>'virtio' — default with QEMU/KVM</li>
|
|
<li>'xen' — default with Xen</li>
|
|
</ul>
|
|
</dd>
|
|
<dt><code>period</code></dt>
|
|
<dd>
|
|
<p>
|
|
The optional <code>period</code> allows the QEMU virtio memory
|
|
balloon driver to provide statistics through the <code>virsh
|
|
dommemstat [domain]</code> command. By default, collection is
|
|
not enabled. In order to enable, use the <code>virsh dommemstat
|
|
[domain] --period [number]</code> command or <code>virsh edit</code>
|
|
command to add the option to the XML definition.
|
|
The <code>virsh dommemstat</code> will accept the options
|
|
<code>--live</code>, <code>--current</code>, or <code>--config</code>.
|
|
If an option is not provided, the change for a running domain will
|
|
only be made to the active guest.
|
|
If the QEMU driver is not at the right
|
|
revision, the attempt to set the period will fail.
|
|
<span class='since'>Since 1.1.1, requires QEMU 1.5</span>
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
<h4><a name="elementsRng">Random number generator device</a></h4>
|
|
|
|
<p>
|
|
The virtual random number generator device allows the host to pass
|
|
through entropy to guest operating systems.
|
|
<span class="since">Since 1.0.3</span>
|
|
</p>
|
|
|
|
<p>
|
|
Example: usage of the RNG device:
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<rng model='virtio'>
|
|
<rate period="2000" bytes="1234"/>
|
|
<backend model='random'>/dev/random</backend>
|
|
<!-- OR -->
|
|
<backend model='egd' type='udp'>
|
|
<source mode='bind' service='1234'/>
|
|
<source mode='connect' host='1.2.3.4' service='1234'/>
|
|
</backend>
|
|
</rng>
|
|
</devices>
|
|
...
|
|
</pre>
|
|
<dl>
|
|
<dt><code>model</code></dt>
|
|
<dd>
|
|
<p>
|
|
The required <code>model</code> attribute specifies what type
|
|
of RNG device is provided. Valid values are specific to
|
|
the virtualization platform:
|
|
</p>
|
|
<ul>
|
|
<li>'virtio' — supported by qemu and virtio-rng kernel module</li>
|
|
</ul>
|
|
</dd>
|
|
<dt><code>rate</code></dt>
|
|
<dd>
|
|
<p>
|
|
The optional <code>rate</code> element allows limiting the rate at
|
|
which entropy can be consumed from the source. The mandatory
|
|
attribute <code>bytes</code> specifies how many bytes are permitted
|
|
to be consumed per period. An optional <code>period</code> attribute
|
|
specifies the duration of a period in milliseconds; if omitted, the
|
|
period is taken as 1000 milliseconds (1 second).
|
|
<span class='since'>Since 1.0.4</span>
|
|
</p>
|
|
</dd>
|
|
<dt><code>backend</code></dt>
|
|
<dd>
|
|
<p>
|
|
The <code>backend</code> element specifies the source of entropy
|
|
to be used for the domain. The source model is configured using the
|
|
<code>model</code> attribute. Supported source models are:
|
|
</p>
|
|
<ul>
|
|
<li>'random' — /dev/random (default) or /dev/hwrng
|
|
device as source (for now, no other sources are permitted)</li>
|
|
<li>'egd' — a EGD protocol backend</li>
|
|
</ul>
|
|
</dd>
|
|
<dt><code>backend model='random'</code></dt>
|
|
<dd>
|
|
<p>
|
|
This backend type expects a non-blocking character device as input.
|
|
The only accepted paths are /dev/random and /dev/hwrng. The file
|
|
name is specified as contents of the <code>backend</code> element.
|
|
When no file name is specified the hypervisor default is used.
|
|
</p>
|
|
</dd>
|
|
<dt><code>backend model='egd'</code></dt>
|
|
<dd>
|
|
<p>
|
|
This backend connects to a source using the EGD protocol.
|
|
The source is specified as a character device. Refer to
|
|
<a href='#elementsCharHostInterface'>character device host interface</a>
|
|
for more information.
|
|
</p>
|
|
</dd>
|
|
|
|
</dl>
|
|
|
|
<h4><a name="elementsTpm">TPM device</a></h4>
|
|
|
|
<p>
|
|
The TPM device enables a QEMU guest to have access to TPM
|
|
functionality.
|
|
</p>
|
|
<p>
|
|
The TPM passthrough device type provides access to the host's TPM
|
|
for one QEMU guest. No other software may be using the TPM device,
|
|
typically /dev/tpm0, at the time the QEMU guest is started.
|
|
<span class="since">'passthrough' since 1.0.5</span>
|
|
</p>
|
|
|
|
<p>
|
|
Example: usage of the TPM passthrough device
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<tpm model='tpm-tis'>
|
|
<backend type='passthrough'>
|
|
<device path='/dev/tpm0'/>
|
|
</backend>
|
|
</tpm>
|
|
</devices>
|
|
...
|
|
</pre>
|
|
<dl>
|
|
<dt><code>model</code></dt>
|
|
<dd>
|
|
<p>
|
|
The <code>model</code> attribute specifies what device
|
|
model QEMU provides to the guest. If no model name is provided,
|
|
<code>tpm-tis</code> will automatically be chosen.
|
|
</p>
|
|
</dd>
|
|
<dt><code>backend</code></dt>
|
|
<dd>
|
|
<p>
|
|
The <code>backend</code> element specifies the type of
|
|
TPM device. The following types are supported:
|
|
</p>
|
|
<ul>
|
|
<li>'passthrough' — use the host's TPM device.</li>
|
|
</ul>
|
|
</dd>
|
|
<dt><code>backend type='passthrough'</code></dt>
|
|
<dd>
|
|
<p>
|
|
This backend type requires exclusive access to a TPM device on
|
|
the host.
|
|
An example for such a device is /dev/tpm0. The filename is
|
|
specified as path attribute of the <code>source</code> element.
|
|
If no file name is specified then /dev/tpm0 is automatically used.
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsNVRAM">NVRAM device</a></h4>
|
|
<p>
|
|
nvram device is always added to pSeries guest on PPC64, and its address
|
|
is allowed to be changed. Element <code>nvram</code> (only valid for
|
|
pSeries guest, <span class="since">since 1.0.5</span>) is provided to
|
|
enable the address setting.
|
|
</p>
|
|
<p>
|
|
Example: usage of NVRAM configuration
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<nvram>
|
|
<address type='spapr-vio' reg='0x3000'/>
|
|
</nvram>
|
|
</devices>
|
|
...
|
|
</pre>
|
|
<dl>
|
|
<dt><code>spapr-vio</code></dt>
|
|
<dd>
|
|
<p>
|
|
VIO device address type, only valid for PPC64.
|
|
</p>
|
|
</dd>
|
|
<dt><code>reg</code></dt>
|
|
<dd>
|
|
<p>
|
|
Device address
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsPanic">panic device</a></h4>
|
|
<p>
|
|
panic device enables libvirt to receive panic notification from a QEMU
|
|
guest.
|
|
<span class="since">Since 1.2.1, QEMU and KVM only</span>
|
|
</p>
|
|
<p>
|
|
Example: usage of panic configuration
|
|
</p>
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<panic>
|
|
<address type='isa' iobase='0x505'/>
|
|
</panic>
|
|
</devices>
|
|
...
|
|
</pre>
|
|
<dl>
|
|
<dt><code>address</code></dt>
|
|
<dd>
|
|
<p>
|
|
address of panic. The default ioport is 0x505. Most users
|
|
don't need to specify an address.
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsShmem">Shared memory device</a></h4>
|
|
|
|
<p>
|
|
A shared memory device allows to share a memory region between
|
|
different virtual machines and the host.
|
|
<span class="since">Since 1.2.10, QEMU and KVM only</span>
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<shmem name='my_shmem0'>
|
|
<size unit='M'>4</size>
|
|
</shmem>
|
|
<shmem name='shmem_server'>
|
|
<size unit='M'>2</size>
|
|
<server path='/tmp/socket-shmem'/>
|
|
<msi vectors='32' ioeventfd='on'/>
|
|
</shmem>
|
|
</devices>
|
|
...
|
|
</pre>
|
|
|
|
<dl>
|
|
<dt><code>shmem</code></dt>
|
|
<dd>
|
|
The <code>shmem</code> element has one mandatory attribute,
|
|
<code>name</code> to identify the shared memory.
|
|
</dd>
|
|
<dt><code>size</code></dt>
|
|
<dd>
|
|
The optional <code>size</code> element specifies the size of the shared
|
|
memory. This must be power of 2 and greater than or equal to 1 MiB.
|
|
</dd>
|
|
<dt><code>server</code></dt>
|
|
<dd>
|
|
The optional <code>server</code> element can be used to configure a server
|
|
socket the device is supposed to connect to. The optional
|
|
<code>path</code> attribute specifies the path to the unix socket and
|
|
defaults to <code>/var/lib/libvirt/shmem/$shmem-$name-sock</code>.
|
|
</dd>
|
|
<dt><code>msi</code></dt>
|
|
<dd>
|
|
The optional <code>msi</code> element enables/disables (values "on"/"off",
|
|
respectively) MSI interrupts. This option can currently be used only
|
|
together with the <code>server</code> element. The <code>vectors</code>
|
|
attribute can be used to specify the number of interrupt
|
|
vectors. The <code>ioeventd</code> attribute enables/disables (values
|
|
"on"/"off", respectively) ioeventfd.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h3><a name="seclabel">Security label</a></h3>
|
|
|
|
<p>
|
|
The <code>seclabel</code> element allows control over the
|
|
operation of the security drivers. There are three basic
|
|
modes of operation, 'dynamic' where libvirt automatically
|
|
generates a unique security label, 'static' where the
|
|
application/administrator chooses the labels, or 'none'
|
|
where confinement is disabled. With dynamic
|
|
label generation, libvirt will always automatically
|
|
relabel any resources associated with the virtual machine.
|
|
With static label assignment, by default, the administrator
|
|
or application must ensure labels are set correctly on any
|
|
resources, however, automatic relabeling can be enabled
|
|
if desired. <span class="since">'dynamic' since 0.6.1, 'static'
|
|
since 0.6.2, and 'none' since 0.9.10.</span>
|
|
</p>
|
|
|
|
<p>
|
|
If more than one security driver is used by libvirt, multiple
|
|
<code>seclabel</code> tags can be used, one for each driver and
|
|
the security driver referenced by each tag can be defined using
|
|
the attribute <code>model</code>
|
|
</p>
|
|
|
|
<p>
|
|
Valid input XML configurations for the top-level security label
|
|
are:
|
|
</p>
|
|
|
|
<pre>
|
|
<seclabel type='dynamic' model='selinux'/>
|
|
|
|
<seclabel type='dynamic' model='selinux'>
|
|
<baselabel>system_u:system_r:my_svirt_t:s0</baselabel>
|
|
</seclabel>
|
|
|
|
<seclabel type='static' model='selinux' relabel='no'>
|
|
<label>system_u:system_r:svirt_t:s0:c392,c662</label>
|
|
</seclabel>
|
|
|
|
<seclabel type='static' model='selinux' relabel='yes'>
|
|
<label>system_u:system_r:svirt_t:s0:c392,c662</label>
|
|
</seclabel>
|
|
|
|
<seclabel type='none'/>
|
|
</pre>
|
|
|
|
<p>
|
|
If no 'type' attribute is provided in the input XML, then
|
|
the security driver default setting will be used, which
|
|
may be either 'none' or 'dynamic'. If a 'baselabel' is set
|
|
but no 'type' is set, then the type is presumed to be 'dynamic'
|
|
</p>
|
|
|
|
<p>
|
|
When viewing the XML for a running guest with automatic
|
|
resource relabeling active, an additional XML element,
|
|
<code>imagelabel</code>, will be included. This is an
|
|
output-only element, so will be ignored in user supplied
|
|
XML documents
|
|
</p>
|
|
<dl>
|
|
<dt><code>type</code></dt>
|
|
<dd>Either <code>static</code>, <code>dynamic</code> or <code>none</code>
|
|
to determine whether libvirt automatically generates a unique security
|
|
label or not.
|
|
</dd>
|
|
<dt><code>model</code></dt>
|
|
<dd>A valid security model name, matching the currently
|
|
activated security model
|
|
</dd>
|
|
<dt><code>relabel</code></dt>
|
|
<dd>Either <code>yes</code> or <code>no</code>. This must always
|
|
be <code>yes</code> if dynamic label assignment is used. With
|
|
static label assignment it will default to <code>no</code>.
|
|
</dd>
|
|
<dt><code>label</code></dt>
|
|
<dd>If static labelling is used, this must specify the full
|
|
security label to assign to the virtual domain. The format
|
|
of the content depends on the security driver in use:
|
|
<ul>
|
|
<li>SELinux: a SELinux context.</li>
|
|
<li>AppArmor: an AppArmor profile.</li>
|
|
<li>
|
|
DAC: owner and group separated by colon. They can be
|
|
defined both as user/group names or uid/gid. The driver will first
|
|
try to parse these values as names, but a leading plus sign can
|
|
used to force the driver to parse them as uid or gid.
|
|
</li>
|
|
</ul>
|
|
</dd>
|
|
<dt><code>baselabel</code></dt>
|
|
<dd>If dynamic labelling is used, this can optionally be
|
|
used to specify the base security label that will be used to generate
|
|
the actual label. The format of the content depends on the security
|
|
driver in use.
|
|
|
|
The SELinux driver uses only the <code>type</code> field of the
|
|
baselabel in the generated label. Other fields are inherited from
|
|
the parent process when using SELinux baselabels.
|
|
|
|
(The example above demonstrates the use of <code>my_svirt_t</code>
|
|
as the value for the <code>type</code> field.)
|
|
</dd>
|
|
<dt><code>imagelabel</code></dt>
|
|
<dd>This is an output only element, which shows the
|
|
security label used on resources associated with the virtual domain.
|
|
The format of the content depends on the security driver in use
|
|
</dd>
|
|
</dl>
|
|
|
|
<p>When relabeling is in effect, it is also possible to fine-tune
|
|
the labeling done for specific source file names, by either
|
|
disabling the labeling (useful if the file lives on NFS or other
|
|
file system that lacks security labeling) or requesting an
|
|
alternate label (useful when a management application creates a
|
|
special label to allow sharing of some, but not all, resources
|
|
between domains), <span class="since">since 0.9.9</span>. When
|
|
a <code>seclabel</code> element is attached to a specific path
|
|
rather than the top-level domain assignment, only the
|
|
attribute <code>relabel</code> or the
|
|
sub-element <code>label</code> are supported. Additionally,
|
|
<span class="since">since 1.1.2</span>, an output-only
|
|
element <code>labelskip</code> will be present for active
|
|
domains on disks where labeling was skipped due to the image
|
|
being on a file system that lacks security labeling.
|
|
</p>
|
|
|
|
<h2><a name="examples">Example configs</a></h2>
|
|
|
|
<p>
|
|
Example configurations for each driver are provide on the
|
|
driver specific pages listed below
|
|
</p>
|
|
|
|
<ul>
|
|
<li><a href="drvxen.html#xmlconfig">Xen examples</a></li>
|
|
<li><a href="drvqemu.html#xmlconfig">QEMU/KVM examples</a></li>
|
|
</ul>
|
|
</body>
|
|
</html>
|