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73c0a148af
In some versions of qemu, both virtio-blk-pci and virtio-net-pci
devices can have an event_idx setting that determines some details of
event processing. When it is enabled, it "reduces the number of
interrupts and exits for the guest". qemu will automatically enable
this feature when it is available, but there may be cases where this
new feature could actually make performance worse (NB: no such case
has been found so far).
As a safety switch in case such a situation is encountered in the
field, this patch adds a new attribute "event_idx" to the <driver>
element of both disk and interface devices. event_idx can be set to
"on" (to force event_idx on in case qemu has it disabled by default)
or "off" (for force event_idx off). In the case that event_idx support
isn't present in qemu, the attribute is ignored (this on the advice of
the qemu developer).
docs/formatdomain.html.in: document the new flag (marking it as
"don't mess with this!"
docs/schemas/domain.rng: add event_idx in appropriate places
src/conf/domain_conf.[ch]: add event_idx to parser and formatter
src/libvirt_private.syms: export
virDomainVirtioEventIdx(From|To)String
src/qemu/qemu_capabilities.[ch]: detect and report event_idx in
disk/net
src/qemu/qemu_command.c: add event_idx parameter to qemu commandline
when appropriate.
tests/qemuxml2argvdata/qemuxml2argv-event_idx.args,
tests/qemuxml2argvdata/qemuxml2argv-event_idx.xml,
tests/qemuxml2argvtest.c,
tests/qemuxml2xmltest.c: test cases for event_idx.
3005 lines
112 KiB
HTML
3005 lines
112 KiB
HTML
<html>
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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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<description>Some human readable description</description>
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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>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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</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>/usr/lib/xen/boot/hvmloader</loader>
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<boot dev='hd'/>
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<boot dev='cdrom'/>
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<bootmenu enable='yes'/>
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<smbios mode='sysinfo'/>
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<bios useserial='yes'/>
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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. At this time, it is
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only needed by Xen fully virtualized
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domains. <span class="since">Since 0.1.0</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. The
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<code>boot</code> element cannot be used if per-device boot elements
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are used (see <a href="#elementsDisks">disks</a>,
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<a href="#elementsNICS">network interfaces</a>, and
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<a href="#elementsUSB">USB and PCI devices</a> sections below).
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<span class="since">Since 0.1.3, per-device boot since 0.8.8</span>
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</dd>
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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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</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.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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<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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</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.
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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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</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 boottime. 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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</dl>
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<h3><a name="elementsSysinfo">SMBIOS System Information</a></h3>
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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>
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<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='vendor'>Virt-Manager</entry>
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</system>
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</sysinfo>
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...</pre>
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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>
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<dt><code>smbios</code></dt>
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<dd>Sub-elements call out specific SMBIOS values, which will
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affect the guest if used in conjunction with
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the <code>smbios</code> sub-element of
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the <a href="#elementsOS"><code>os</code></a> element. Each
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sub-element of <code>sysinfo</code> names a SMBIOS block, and
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within those elements can be a list of <code>entry</code>
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elements that describe a field within the block. The following
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blocks and entries are recognized:
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<dl>
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<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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"vendor", "version", "date", and "release".
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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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"manufacturer", "product", "version", "serial", "uuid",
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"sku", and "family". If a "uuid" entry is provided
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alongside a
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top-level <a href="#elementsMetadata"><code>uuid</code>
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element</a>, the two values must match.
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</dd>
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</dl>
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</dd>
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</dl>
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<h3><a name="elementsCPUAllocation">CPU Allocation</a></h3>
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<pre>
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<domain>
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...
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<vcpu cpuset="1-4,^3,6" current="1">2</vcpu>
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...
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</domain>
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</pre>
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<dl>
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<dt><code>vcpu</code></dt>
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<dd>The content of this element defines the maximum number of virtual
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CPUs allocated for the guest OS, which must be between 1 and
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the maximum supported by the hypervisor. <span class="since">Since
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0.4.4</span>, this element can contain an optional
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<code>cpuset</code> attribute, which is a comma-separated
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list of physical CPU numbers that virtual CPUs can be pinned
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to. Each element in that list is either a single CPU number,
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a range of CPU numbers, or a caret followed by a CPU number to
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be excluded from a previous range. <span class="since">Since
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0.8.5</span>, the optional attribute <code>current</code> can
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be used to specify whether fewer than the maximum number of
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virtual CPUs should be enabled.
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</dd>
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</dl>
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<h3><a name="elementsCPUTuning">CPU Tuning</a></h3>
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<pre>
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<domain>
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...
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<cputune>
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<vcpupin vcpu="0" cpuset="1-4,^2"/>
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<vcpupin vcpu="1" cpuset="0,1"/>
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<vcpupin vcpu="2" cpuset="2,3"/>
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<vcpupin vcpu="3" cpuset="0,4"/>
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<shares>2048</shares>
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<period>1000000</period>
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<quota>-1</quota>
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</cputune>
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...
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</domain>
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</pre>
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<dl>
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<dt><code>cputune</code></dt>
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<dd>
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The optional <code>cputune</code> element provides details
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regarding the cpu tunable parameters for the domain.
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<span class="since">Since 0.9.0</span>
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</dd>
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<dt><code>vcpupin</code></dt>
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<dd>
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The optional <code>vcpupin</code> element specifies which of host
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physical CPUS the domain VCPU will be pinned to. If this is ommited,
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each VCPU pinned to all the physical CPUS by default. It contains two
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required attributes, the attribute <code>vcpu</code> specifies vcpu id,
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and the attribute <code>cpuset</code> is same as
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attribute <code>cpuset</code>
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of element <code>vcpu</code>. (NB: Only qemu driver support)
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<span class="since">Since 0.9.0</span>
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</dd>
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<dt><code>shares</code></dt>
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<dd>
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The optional <code>shares</code> element specifies the proportional
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weighted share for the domain. If this is ommited, it defaults to
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the OS provided defaults. NB, There is no unit for the value,
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it's a relative measure based on the setting of other VM,
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e.g. A VM configured with value
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2048 will get twice as much CPU time as a VM configured with value 1024.
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<span class="since">Since 0.9.0</span>
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</dd>
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<dt><code>period</code></dt>
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<dd>
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The optional <code>period</code> element specifies the enforcement
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interval(unit: microseconds). Within <code>period</code>, each vcpu of
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the domain will not be allowed to consume more than <code>quota</code>
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worth of runtime. The value should be in range [1000, 1000000]. A period
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with value 0 means no value. (NB: Only qemu driver support)
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<span class="since">Since 0.9.4</span>
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</dd>
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<dt><code>quota</code></dt>
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<dd>
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The optional <code>quota</code> element specifies the maximum allowed
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bandwidth(unit: microseconds). A domain with <code>quota</code> as any
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negative value indicates that the domain has infinite bandwidth, which
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means that it is not bandwidth controlled. The value should be in range
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[1000, 18446744073709551] or less than 0. A quota with value 0 means no
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value. You can use this feature to ensure that all vcpus run at the same
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speed. (NB: Only qemu driver support)
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<span class="since">Since 0.9.4</span>
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</dd>
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</dl>
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|
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<h3><a name="elementsMemoryAllocation">Memory Allocation</a></h3>
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|
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<pre>
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<domain>
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...
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<memory>524288</memory>
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<currentMemory>524288</currentMemory>
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...
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</domain>
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</pre>
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|
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<dl>
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<dt><code>memory</code></dt>
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<dd>The maximum allocation of memory for the guest at boot time.
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The units for this value are kilobytes (i.e. blocks of 1024 bytes)</dd>
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<dt><code>currentMemory</code></dt>
|
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<dd>The actual allocation of memory for the guest. This value can
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be less than the maximum allocation, to allow for ballooning
|
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up the guests memory on the fly. If this is omitted, it defaults
|
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to the same value as the <code>memory</code> element</dd>
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</dl>
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|
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<h3><a name="elementsMemoryBacking">Memory Backing</a></h3>
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|
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<pre>
|
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<domain>
|
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...
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<memoryBacking>
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<hugepages/>
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</memoryBacking>
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...
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</domain>
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</pre>
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|
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<dl>
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<dt><code>memoryBacking</code></dt>
|
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<dd>The optional <code>memoryBacking</code> element, may have an
|
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<code>hugepages</code> element set within it. This tells the
|
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hypervisor that the guest should have its memory allocated using
|
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hugepages instead of the normal native page size.</dd>
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</dl>
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|
|
|
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<h3><a name="elementsMemoryTuning">Memory Tuning</a></h3>
|
|
|
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<pre>
|
|
<domain>
|
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...
|
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<memtune>
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<hard_limit>1048576</hard_limit>
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<soft_limit>131072</soft_limit>
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<swap_hard_limit>2097152</swap_hard_limit>
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<min_guarantee>65536</min_guarantee>
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</memtune>
|
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...
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</domain>
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|
</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.</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 kilobytes (i.e. blocks
|
|
of 1024 bytes)</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
|
|
kilobytes (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
|
|
kilobytes (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
|
|
kilobytes (i.e. blocks of 1024 bytes)</dd>
|
|
</dl>
|
|
|
|
|
|
<h3><a name="elementsNUMATuning">NUMA Node Tuning</a></h3>
|
|
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<numatune>
|
|
<memory mode="strict" nodeset="1-4,^3"/>
|
|
</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>
|
|
<dt><code>memory</code></dt>
|
|
<dd>
|
|
The optional <code>memory</code> element specify how to allocate memory
|
|
for the domain process on a NUMA host. It contains two attributes,
|
|
attribute <code>mode</code> is either 'interleave', 'strict',
|
|
or 'preferred',
|
|
attribute <code>nodeset</code> specifies the NUMA nodes, it leads same
|
|
syntax with attribute <code>cpuset</code> of element <code>vcpu</code>.
|
|
<span class='since'>Since 0.9.3</span>
|
|
</dd>
|
|
</dl>
|
|
|
|
|
|
<h3><a name="elementsBlockTuning">Block I/O Tuning</a></h3>
|
|
<pre>
|
|
<domain>
|
|
...
|
|
<blkiotune>
|
|
<weight>800</weight>
|
|
</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.</dd>
|
|
<dt><code>weight</code></dt>
|
|
<dd> The optional <code>weight</code> element is the I/O weight of the
|
|
guest. The value should be in range [100, 1000].</dd>
|
|
</dl>
|
|
|
|
|
|
<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>core2duo</model>
|
|
<vendor>Intel</vendor>
|
|
<topology sockets='1' cores='2' threads='1'/>
|
|
<feature policy='disable' name='lahf_lm'/>
|
|
</cpu>
|
|
...</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>.
|
|
</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.</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>
|
|
|
|
<h3><a name="elementsLifecycle">Lifecycle control</a></h3>
|
|
|
|
<p>
|
|
It is sometimes necessary to override the default actions taken
|
|
when a guest OS triggers a lifecycle operation. The following
|
|
collections of elements allow the actions to be specified. 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>
|
|
|
|
<pre>
|
|
...
|
|
<on_poweroff>destroy</on_poweroff>
|
|
<on_reboot>restart</on_reboot>
|
|
<on_crash>restart</on_crash>
|
|
...</pre>
|
|
|
|
<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>
|
|
on_crash 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>
|
|
|
|
<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/>
|
|
</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>hap</code></dt>
|
|
<dd>Enable use of Hardware Assisted Paging if available in
|
|
the hardware.
|
|
</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="none"/>
|
|
</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</dd>
|
|
<dt><code>localtime</code></dt>
|
|
<dd>
|
|
The guest clock will be synchronized to the host's configured
|
|
timezone when booted, if any.
|
|
</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. The delta relative to UTC is specified
|
|
in seconds, using the <code>adjustment</code> attribute.
|
|
The guest is free to adjust the RTC over time an expect
|
|
that it will be honoured at next reboot. This is in
|
|
contrast to 'utc' mode, where the RTC adjustments are
|
|
lost at each reboot. <span class="since">Since 0.7.7</span>
|
|
</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", "pit",
|
|
"rtc", "hpet", or "tsc".
|
|
</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>
|
|
The <code>tickpolicy</code> attribute determines how
|
|
missed ticks in the guest are handled, and can be "delay",
|
|
"catchup", "merge", or "discard". If the policy is
|
|
"catchup", there can be further details in
|
|
the <code>catchup</code> sub-element.
|
|
<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>
|
|
</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'>
|
|
<driver name="tap" type="aio" cache="default"/>
|
|
<source file='/var/lib/xen/images/fv0'/>
|
|
<target dev='hda' bus='ide'/>
|
|
<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'/>
|
|
<address type='drive' controller='0' bus='1' unit='0'/>
|
|
</disk>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>disk</code></dt>
|
|
<dd>The <code>disk</code> element is the main container for describing
|
|
disks. The <code>type</code> attribute is either "file",
|
|
"block", "dir", or "network"
|
|
and refers to the underlying source for the disk. The optional
|
|
<code>device</code> attribute indicates how the disk is to be exposed
|
|
to the guest OS. Possible values for this attribute are "floppy", "disk"
|
|
and "cdrom", defaulting to "disk".
|
|
<span class="since">Since 0.0.3; "device" attribute since 0.1.4;
|
|
"network" attribute since 0.8.7</span></dd>
|
|
<dt><code>source</code></dt>
|
|
<dd>If the disk <code>type</code> is "file", then
|
|
the <code>file</code> attribute specifies the fully-qualified
|
|
path to the file holding the disk. If the disk
|
|
<code>type</code> is "block", then the <code>dev</code>
|
|
attribute specifies the path to the host device to serve as
|
|
the disk. If the disk <code>type</code> is "network", then
|
|
the <code>protocol</code> attribute specifies the protocol to
|
|
access to the requested image; possible values are "nbd",
|
|
"rbd", and "sheepdog". If the <code>protocol</code> attribute
|
|
is "rbd" or "sheepdog", an additional
|
|
attribute <code>name</code> is mandatory to specify which
|
|
image to be used. 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.
|
|
<span class="since">Since 0.0.3</span></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" or "usb". If omitted, the bus type is
|
|
inferred from the style of the device name. eg, a device named 'sda'
|
|
will typically be exported using a SCSI bus.
|
|
<span class="since">Since 0.0.3; <code>bus</code> attribute since 0.4.3;
|
|
"usb" attribute value since after 0.4.4</span></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" and "writeback".
|
|
<span class="since">Since 0.6.0</span>
|
|
</li>
|
|
<li>
|
|
The optional <code>error_policy</code> attribute controls
|
|
how the hypervisor will behave on an error, possible
|
|
values are "stop", "ignore", and "enospace".
|
|
<span class="since">Since 0.8.0</span>
|
|
</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 interupts 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>
|
|
</ul>
|
|
</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>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>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>host</code></dt>
|
|
<dd>The <code>host</code> element has two attributes "name" and "port",
|
|
which specify the hostname and the port number. The meaning of this
|
|
element and the number of the elements depend on the protocol attribute.
|
|
<table class="top_table">
|
|
<tr>
|
|
<th> Protocol </th>
|
|
<th> Meaning </th>
|
|
<th> Number of hosts </th>
|
|
</tr>
|
|
<tr>
|
|
<td> nbd </td>
|
|
<td> a server running nbd-server </td>
|
|
<td> only one </td>
|
|
</tr>
|
|
<tr>
|
|
<td> rbd </td>
|
|
<td> monitor servers of RBD </td>
|
|
<td> one or more </td>
|
|
</tr>
|
|
<tr>
|
|
<td> sheepdog </td>
|
|
<td> one of the sheepdog servers (default is localhost:7000) </td>
|
|
<td> zero or one </td>
|
|
</tr>
|
|
</table>
|
|
</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 an
|
|
optional <code>domain</code>. For a "drive" controller,
|
|
additional attributes <code>controller</code>, <code>bus</code>,
|
|
and <code>unit</code> are available, each defaulting to 0.
|
|
</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'>
|
|
<source dir='/export/to/guest'/>
|
|
<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.
|
|
</dd>
|
|
<dt><code>type='template'</code></dt>
|
|
<dd>
|
|
OpenVZ filesystem template. Only used by OpenVZ driver.
|
|
</dd>
|
|
<dt><code>type='file'</code></dt>
|
|
<dd>
|
|
Currently unused.
|
|
</dd>
|
|
<dt><code>type='block'</code></dt>
|
|
<dd>
|
|
Currently unused.
|
|
</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>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>
|
|
</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>
|
|
An optional <code>readonly</code> attribute is available but currently
|
|
unused.
|
|
</dd>
|
|
</dl>
|
|
|
|
<h4><a name="elementsControllers">Controllers</a></h4>
|
|
|
|
<p>
|
|
Many devices that have an <code><address></code>
|
|
sub-element are designed to work with a controller to manage
|
|
related devices. 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", "ccid", or
|
|
"virtio-serial", 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", "lsilogic", "lsias1068", or "vmpvscsi".
|
|
</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 like any other device's <code>address</code>
|
|
sub-element.
|
|
</p>
|
|
|
|
<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="elementsUSB">USB and PCI devices</a></h4>
|
|
|
|
<p>
|
|
USB and PCI 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 and 0.6.0 for PCI (KVM only)</span>:
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<hostdev mode='subsystem' type='usb'>
|
|
<source>
|
|
<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 bus='0x06' slot='0x02' function='0x0'/>
|
|
</source>
|
|
<boot order='1'/>
|
|
</hostdev>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>hostdev</code></dt>
|
|
<dd>The <code>hostdev</code> element is the main container for describing
|
|
host devices. For usb device passthrough <code>mode</code> is always
|
|
"subsystem" and <code>type</code> is "usb" for a USB device and "pci"
|
|
for a PCI device. When <code>managed</code> is "yes" for a PCI
|
|
device, it is detached from the host before being passed on to
|
|
the guest.</dd>
|
|
<dt><code>source</code></dt>
|
|
<dd>The source element describes the device as seen from the host.
|
|
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 hosts using the <code>address</code> element.
|
|
PCI devices on the other hand can only be described by their
|
|
<code>address</code></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></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 3 attributes allowing to designate
|
|
the device as can be found with the <code>lspci</code> or
|
|
with <code>virsh nodedev-list</code>. The
|
|
<code>bus</code> attribute allows the hexadecimal values 0 to ff, the
|
|
<code>slot</code> attribute allows the hexadecimal values 0 to 1f, and
|
|
the <code>function</code> attribute allows the hexadecimal values 0 to
|
|
7. There is also an optional <code>domain</code> attribute for the
|
|
PCI domain, with hexadecimal values 0 to ffff, but it is currently
|
|
not used by qemu.</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.
|
|
If present, the element must have an attribute
|
|
of <code>type='ccid'</code> as well as a <code>bus</code>
|
|
attribute listing the index of the bus that the smartcard
|
|
utilizes. An optional <code>slot</code> attribute lists which
|
|
slot within the bus. 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='bridge'>
|
|
<source bridge='xenbr0'/>
|
|
<mac address='00:16:3e:5d:c7:9e'/>
|
|
<script path='vif-bridge'/>
|
|
<boot order='1'/>
|
|
</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. Additionally,
|
|
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> and additional
|
|
attributes <code>domain</code>, <code>bus</code>, <code>slot</code>,
|
|
and <code>function</code> as appropriate.
|
|
</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>). Also,
|
|
similar to <code>direct</code> network connections (described
|
|
below), a connection of type <code>network</code> may specify
|
|
a <code>virtportprofile</code> element, with configuration data
|
|
to be forwarded to a vepa or 802.1Qbh compliant switch.
|
|
</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 type='802.1Qbg'>
|
|
<parameters managerid='11' typeid='1193047' typeidversion='2' 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 onto 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>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='bridge'>
|
|
<source bridge='br0'/>
|
|
</interface>
|
|
...
|
|
<interface type='bridge'>
|
|
<source bridge='br0'/>
|
|
<target dev='vnet7'/>
|
|
<mac address="00:11:22:33:44:55"/>
|
|
</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
|
|
physial 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>
|
|
|
|
<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'/>
|
|
...
|
|
<interface type='direct'>
|
|
<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'/>
|
|
...
|
|
<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 onto 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'/>
|
|
...
|
|
<interface type='direct'>
|
|
<source dev='eth0' mode='private'/>
|
|
<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'>
|
|
<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'>
|
|
<source address='192.168.0.1' port='5558'/>
|
|
</interface>
|
|
...
|
|
<interface type='client'>
|
|
<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'/></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>
|
|
<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 interupts 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>
|
|
</dl>
|
|
|
|
<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 specifed, 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>
|
|
|
|
<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 exact NIC which should
|
|
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="elementQoS">Quality of service</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
<target dev='vnet0'/>
|
|
<b><bandwidth>
|
|
<inbound average='1000' peak='5000' 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 can have at most one <code>inbound</code>
|
|
and at most one <code>outbound</code> child elements. Leaving any of these
|
|
children element out result in no QoS applied on that traffic direction.
|
|
So, when you want to shape only domain's incoming traffic, use
|
|
<code>inbound</code> only, and vice versa. Each of these elements have one
|
|
mandatory attribute <code>average</code>. It specifies average bit rate on
|
|
interface being shaped. Then there are two optional attributes:
|
|
<code>peak</code>, which specifies maximum rate at which interface can send
|
|
data, and <code>burst</code>, amount of bytes that can be burst at
|
|
<code>peak</code> speed. Accepted values for attributes are integer
|
|
numbers. The units for <code>average</code> and <code>peak</code> attributes
|
|
are kilobytes per second, and for the <code>burst</code> just kilobytes.
|
|
<span class="since">Since 0.9.4</span>
|
|
</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'/>
|
|
</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 either 'mouse' or
|
|
'tablet'. The latter provides absolute
|
|
cursor movement, while the former 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.
|
|
</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'>
|
|
<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/> <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>
|
|
</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
|
|
both 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>.
|
|
</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. Valid channel names
|
|
include <code>main</code>, <code>display</code>,
|
|
<code>inputs</code>, <code>cursor</code>,
|
|
<code>playback</code>, <code>record</code>;
|
|
and <span class="since">since
|
|
0.8.8</span>: <code>smartcard</code>.
|
|
</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'/>
|
|
</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 it's <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>
|
|
</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> 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='8192' heads='1'>
|
|
<acceleration accel3d='yes' accel3d='yes'/>
|
|
</model>
|
|
</video>
|
|
</devices>
|
|
...</pre>
|
|
|
|
<dl>
|
|
<dt><code>video</code></dt>
|
|
<dd>
|
|
The <code>video</code> element is the a container for describing
|
|
video devices. For backwards compatability, 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.
|
|
For a guest of type "kvm", the default <code>video</code> for it is:
|
|
<code>type</code> with value "cirrus", <code>vram</code> with value
|
|
"9216", and <code>heads</code> with value "1".
|
|
</dd>
|
|
|
|
<dt><code>model</code></dt>
|
|
<dd>
|
|
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.
|
|
You can also provide the amount of video memory in kilobytes using
|
|
<code>vram</code> and the number of screen with <code>heads</code>.
|
|
</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>
|
|
<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>
|
|
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.
|
|
</p>
|
|
|
|
<h6><a name="elementCharConsole">Console</a></h6>
|
|
|
|
<p>
|
|
This represents the primary console. This can be the paravirtualized
|
|
console with Xen guests, virtio console for QEMU/KVM, or duplicates
|
|
the primary serial port for fully virtualized guests without a
|
|
paravirtualized console.
|
|
</p>
|
|
|
|
<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>
|
|
|
|
<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='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.
|
|
<span class="since">Since 0.7.7</span></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>
|
|
|
|
|
|
<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', and 'ich6'
|
|
(<span class="since">
|
|
'ac97' only since 0.6.0, 'ich6' only since 0.8.8</span>)
|
|
</dd>
|
|
</dl>
|
|
|
|
<p>
|
|
Each <code>sound</code> element has an optional
|
|
sub-element <code><address></code> which can tie the
|
|
device to a particular PCI slot.
|
|
</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>
|
|
<watchdog model='virtio'/>
|
|
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
|
|
</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>
|
|
</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 two basic
|
|
modes of operation, dynamic where libvirt automatically
|
|
generates a unique security label, or static where the
|
|
application/administrator chooses the labels. 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
|
|
</p>
|
|
|
|
<p>
|
|
Valid input XML configurations for the 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>
|
|
</pre>
|
|
|
|
<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> or <code>dynamic</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
|
|
</dd>
|
|
<dt><code>baselabel</code></dt>
|
|
<dd>If dynamic labelling is used, this can optionally be
|
|
used to specify the base security label. The format
|
|
of the content depends on the security driver in use
|
|
</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>
|
|
|
|
<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>
|