mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2024-12-23 06:05:27 +00:00
176 lines
12 KiB
HTML
176 lines
12 KiB
HTML
<?xml version="1.0" encoding="ISO-8859-1"?>
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" /><link rel="stylesheet" type="text/css" href="libvirt.css" /><link rel="SHORTCUT ICON" href="/32favicon.png" /><title>Connection URIs</title></head><body><div id="container"><div id="intro"><div id="adjustments"></div><div id="pageHeader"></div><div id="content2"><h1 class="style1">Connection URIs</h1><p>
|
|
Since libvirt supports many different kinds of virtualization
|
|
(often referred to as "drivers" or "hypervisors"), we need a
|
|
way to be able to specify which driver a connection refers to.
|
|
Additionally we may want to refer to a driver on a remote
|
|
machine over the network.
|
|
</p><p>
|
|
To this end, libvirt uses URIs as used on the Web and as defined in <a href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>. This page
|
|
documents libvirt URIs.
|
|
</p><ul><li><a href="#URI_libvirt">Specifying URIs to libvirt</a></li>
|
|
<li><a href="#URI_virsh">Specifying URIs to virsh, virt-manager and virt-install</a></li>
|
|
<li><a href="#URI_xen">xen:/// URI</a></li>
|
|
<li><a href="#URI_qemu">qemu:///... QEMU and KVM URIs</a></li>
|
|
<li><a href="#URI_remote">Remote URIs</a></li>
|
|
<li><a href="#URI_test">test:///... Test URIs</a></li>
|
|
<li><a href="#URI_legacy">Other & legacy URI formats</a></li>
|
|
</ul><h3><a name="URI_libvirt" id="URI_libvirt">Specifying URIs to libvirt</a></h3><p>
|
|
The URI is passed as the <code>name</code> parameter to <a href="html/libvirt-libvirt.html#virConnectOpen"><code>virConnectOpen</code></a> or <a href="html/libvirt-libvirt.html#virConnectOpenReadOnly"><code>virConnectOpenReadOnly</code></a>. For example:
|
|
</p><pre>
|
|
virConnectPtr conn = virConnectOpenReadOnly (<b>"test:///default"</b>);
|
|
</pre><h3><a name="URI_virsh" id="URI_virsh">Specifying URIs to virsh, virt-manager and virt-install</a></h3><p>
|
|
In virsh use the <code>-c</code> or <code>--connect</code> option:
|
|
</p><pre>
|
|
virsh <b>-c test:///default</b> list
|
|
</pre><p>
|
|
If virsh finds the environment variable
|
|
<code>VIRSH_DEFAULT_CONNECT_URI</code> set, it will try this URI by
|
|
default.
|
|
</p><p>
|
|
When using the interactive virsh shell, you can also use the
|
|
<code>connect</code> <i>URI</i> command to reconnect to another
|
|
hypervisor.
|
|
</p><p>
|
|
In virt-manager use the <code>-c</code> or <code>--connect=</code><i>URI</i> option:
|
|
</p><pre>
|
|
virt-manager <b>-c test:///default</b>
|
|
</pre><p>
|
|
In virt-install use the <code>--connect=</code><i>URI</i> option:
|
|
</p><pre>
|
|
virt-install <b>--connect=test:///default</b> <i>[other options]</i>
|
|
</pre><h3><a name="URI_xen" id="URI_xen">xen:/// URI</a></h3><p><i>This section describes a feature which is new in libvirt >
|
|
0.2.3. For libvirt ≤ 0.2.3 use <a href="#URI_legacy_xen"><code>"xen"</code></a>.</i>
|
|
</p><p>
|
|
To access a Xen hypervisor running on the local machine
|
|
use the URI <code>xen:///</code>.
|
|
</p><h3><a name="URI_qemu" id="URI_qemu">qemu:///... QEMU and KVM URIs</a></h3><p>
|
|
To use QEMU support in libvirt you must be running the
|
|
<code>libvirtd</code> daemon (named <code>libvirt_qemud</code>
|
|
in releases prior to 0.3.0). The purpose of this
|
|
daemon is to manage qemu instances.
|
|
</p><p>
|
|
The <code>libvirtd</code> daemon can be run in two ways. It may
|
|
be started by init scripts when the machine boots and run in "system
|
|
mode" (<code>libvirtd --system</code>), in which case it manages
|
|
qemu instances on behalf of all users of the machine. It may be also
|
|
be started by the local user in what is known as "session mode"
|
|
(<code>libvirtd --session</code>), to manage qemu instances for
|
|
just the current user. If no <code>libvirtd</code> is running at
|
|
all, then the qemu driver starts one running in session mode.
|
|
</p><p>
|
|
So to connect to the daemon, one of two different URIs is used:
|
|
</p><ul><li> <code>qemu:///system</code> connects to a system mode daemon. </li>
|
|
<li> <code>qemu:///session</code> connects to a session mode daemon. </li>
|
|
</ul><p>
|
|
(If you do <code>libvirtd --help</code>, the daemon will print
|
|
out the paths of the Unix domain socket(s) that it listens on in
|
|
the various different modes).
|
|
</p><p>
|
|
KVM URIs are identical. You select between qemu, qemu accelerated and
|
|
KVM guests in the <a href="format.html#KVM1">guest XML as described
|
|
here</a>.
|
|
</p><h3><a name="URI_remote" id="URI_remote">Remote URIs</a></h3><p>
|
|
Remote URIs are formed by taking ordinary local URIs and adding a
|
|
hostname and/or transport name. For example:
|
|
</p><table class="top_table"><tr><th> Local URI </th>
|
|
<th> Remote URI </th>
|
|
<th> Meaning </th>
|
|
</tr><tr><td> <code>xen:///</code> </td>
|
|
<td> <code>xen://oirase/</code> </td>
|
|
<td> Connect to the Xen hypervisor running on host <code>oirase</code>
|
|
using TLS. </td>
|
|
</tr><tr><td> <code>xen:///</code> </td>
|
|
<td> <code>xen+ssh://oirase/</code> </td>
|
|
<td> Connect to the Xen hypervisor running on host <code>oirase</code>
|
|
by going over an <code>ssh</code> connection. </td>
|
|
</tr><tr><td> <code>test:///default</code> </td>
|
|
<td> <code>test+tcp://oirase/default</code> </td>
|
|
<td> Connect to the test driver on host <code>oirase</code>
|
|
using an unsecured TCP connection. </td>
|
|
</tr></table><p>
|
|
Remote URIs in libvirt offer a rich syntax and many features.
|
|
We refer you to <a href="remote.html#Remote_URI_reference">the libvirt
|
|
remote URI reference</a> and <a href="remote.html">full documentation
|
|
for libvirt remote support</a>.
|
|
</p><h3><a name="URI_test" id="URI_test">test:///... Test URIs</a></h3><p>
|
|
The test driver is a dummy hypervisor for test purposes.
|
|
The URIs supported are:
|
|
</p><ul><li> <code>test:///default</code> connects to a default set of
|
|
host definitions built into the driver. </li>
|
|
<li> <code>test:///path/to/host/definitions</code> connects to
|
|
a set of host definitions held in the named file.
|
|
</li></ul><h3><a name="URI_legacy" id="URI_legacy">Other & legacy URI formats</a></h3><h4><a name="URI_NULL" id="URI_NULL">NULL and empty string URIs</a></h4><p>
|
|
Libvirt allows you to pass a <code>NULL</code> pointer to
|
|
<code>virConnectOpen*</code>. Empty string (<code>""</code>) acts in
|
|
the same way. Traditionally this has meant
|
|
<q>connect to the local Xen hypervisor</q>. However in future this
|
|
may change to mean <q>connect to the best available hypervisor</q>.
|
|
</p><p>
|
|
The theory is that if, for example, Xen is unavailable but the
|
|
machine is running an OpenVZ kernel, then we should not try to
|
|
connect to the Xen hypervisor since that is obviously the wrong
|
|
thing to do.
|
|
</p><p>
|
|
In any case applications linked to libvirt can continue to pass
|
|
<code>NULL</code> as a default choice, but should always allow the
|
|
user to override the URI, either by constructing one or by allowing
|
|
the user to type a URI in directly (if that is appropriate). If your
|
|
application wishes to connect specifically to a Xen hypervisor, then
|
|
for future proofing it should choose a full <a href="#URI_xen"><code>xen:///</code> URI</a>.
|
|
</p><h4><a name="URI_file" id="URI_file">File paths (xend-unix-server)</a></h4><p>
|
|
If XenD is running and configured in <code>/etc/xen/xend-config.sxp</code>:
|
|
</p><pre>
|
|
(xend-unix-server yes)
|
|
</pre><p>
|
|
then it listens on a Unix domain socket, usually at
|
|
<code>/var/lib/xend/xend-socket</code>. You may pass a different path
|
|
using a file URI such as:
|
|
</p><pre>
|
|
virsh -c ///var/run/xend/xend-socket
|
|
</pre><h4><a name="URI_http" id="URI_http">Legacy: <code>http://...</code> (xend-http-server)</a></h4><p>
|
|
If XenD is running and configured in <code>/etc/xen/xend-config.sxp</code>:
|
|
|
|
</p><pre>
|
|
(xend-http-server yes)
|
|
</pre><p>
|
|
then it listens on TCP port 8000. libvirt allows you to
|
|
try to connect to xend running on remote machines by passing
|
|
<code>http://<i>hostname</i>[:<i>port</i>]/</code>, for example:
|
|
|
|
</p><pre>
|
|
virsh -c http://oirase/ list
|
|
</pre><p>
|
|
This method is unencrypted and insecure and is definitely not
|
|
recommended for production use. Instead use <a href="remote.html">libvirt's remote support</a>.
|
|
</p><p>
|
|
Notes:
|
|
</p><ol><li> The HTTP client does not fully support IPv6. </li>
|
|
<li> Many features do not work as expected across HTTP connections, in
|
|
particular, <a href="html/libvirt-libvirt.html#virConnectGetCapabilities">virConnectGetCapabilities</a>.
|
|
The <a href="remote.html">remote support</a> however does work
|
|
correctly. </li>
|
|
<li> XenD's new-style XMLRPC interface is not supported by
|
|
libvirt, only the old-style sexpr interface known in the Xen
|
|
documentation as "unix server" or "http server".</li>
|
|
</ol><h4><a name="URI_legacy_xen" id="URI_legacy_xen">Legacy: <code>"xen"</code></a></h4><p>
|
|
Another legacy URI is to specify name as the string
|
|
<code>"xen"</code>. This will continue to refer to the Xen
|
|
hypervisor. However you should prefer a full <a href="#URI_xen"><code>xen:///</code> URI</a> in all future code.
|
|
</p><h4><a name="URI_http" id="URI_http">Legacy: Xen proxy</a></h4><p>
|
|
Libvirt continues to support connections to a separately running Xen
|
|
proxy daemon. This provides a way to allow non-root users to make a
|
|
safe (read-only) subset of queries to the hypervisor.
|
|
</p><p>
|
|
There is no specific "Xen proxy" URI. However if a Xen URI of any of
|
|
the ordinary or legacy forms is used (eg. <code>NULL</code>,
|
|
<code>""</code>, <code>"xen"</code>, ...) which fails, <i>and</i> the
|
|
user is not root, <i>and</i> the Xen proxy socket can be connected to
|
|
(<code>/tmp/libvirt_proxy_conn</code>), then libvirt will use a proxy
|
|
connection.
|
|
</p><p>
|
|
You should consider using <a href="remote.html">libvirt remote support</a>
|
|
in future.
|
|
</p></div></div><div class="linkList2"><div class="llinks2"><h3 class="links2"><span>main menu</span></h3><ul><li><a href="index.html">Home</a></li><li><a href="news.html">Releases</a></li><li><a href="intro.html">Introduction</a></li><li><a href="architecture.html">libvirt architecture</a></li><li><a href="downloads.html">Downloads</a></li><li><a href="format.html">XML Format</a></li><li><a href="python.html">Binding for Python</a></li><li><a href="errors.html">Handling of errors</a></li><li><a href="FAQ.html">FAQ</a></li><li><a href="bugs.html">Reporting bugs and getting help</a></li><li><a href="remote.html">Remote support</a></li><li><a href="uri.html">Connection URIs</a></li><li><a href="hvsupport.html">Hypervisor support</a></li><li><a href="html/index.html">API Menu</a></li><li><a href="examples/index.html">C code examples</a></li><li><a href="ChangeLog.html">Recent Changes</a></li></ul></div><div class="llinks2"><h3 class="links2"><span>related links</span></h3><ul><li><a href="https://www.redhat.com/archives/libvir-list/">Mail archive</a></li><li><a href="https://bugzilla.redhat.com/bugzilla/buglist.cgi?product=Fedora+Core&component=libvirt&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&bug_status=MODIFIED&short_desc_type=allwordssubstr&short_desc=&long_desc_type=allwordssubstr">Open bugs</a></li><li><a href="http://virt-manager.et.redhat.com/">virt-manager</a></li><li><a href="http://search.cpan.org/~danberr/Sys-Virt-0.1.0/">Perl bindings</a></li><li><a href="http://et.redhat.com/~rjones/ocaml-libvirt/">OCaml bindings</a></li><li><a href="http://www.cl.cam.ac.uk/Research/SRG/netos/xen/index.html">Xen project</a></li><li><form action="search.php" enctype="application/x-www-form-urlencoded" method="get"><input name="query" type="text" size="12" value="Search..." /><input name="submit" type="submit" value="Go" /></form></li><li><a href="http://xmlsoft.org/"><img src="Libxml2-Logo-90x34.gif" alt="Made with Libxml2 Logo" /></a></li></ul><p class="credits">Graphics and design by <a href="mail:dfong@redhat.com">Diana Fong</a></p></div></div><div id="bottom"><p class="p1"></p></div></div></body></html>
|