mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2024-07-30 13:37:17 +00:00
f2f9742d4d
The rule generating the HTML docs passing the --html flag to xsltproc. This makes it use the legacy HTML parser, which either ignores or tries to fix all sorts of broken XML tags. There's no reason why we should be writing broken XML in the first place, so removing --html and adding the XHTML doctype to all files forces us to create good XML. This adds the XHTML doc type and fixes many, many XML tag problems it exposes. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
142 lines
4.1 KiB
XML
142 lines
4.1 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
|
|
<html xmlns="http://www.w3.org/1999/xhtml">
|
|
<body>
|
|
<h1>LXC container driver</h1>
|
|
<p>
|
|
The libvirt LXC driver manages "Linux Containers". Containers are sets of processes
|
|
with private namespaces which can (but don't always) look like separate machines, but
|
|
do not have their own OS. Here are two example configurations. The first is a very
|
|
light-weight "application container" which does not have its own root image.
|
|
</p>
|
|
|
|
<h2><a name="project">Project Links</a></h2>
|
|
|
|
<ul>
|
|
<li>
|
|
The <a href="http://lxc.sourceforge.net/">LXC</a> Linux
|
|
container system
|
|
</li>
|
|
</ul>
|
|
|
|
<h2>Cgroups Requirements</h2>
|
|
|
|
<p>
|
|
The libvirt LXC driver requires that certain cgroups controllers are
|
|
mounted on the host OS. The minimum required controllers are 'cpuacct',
|
|
'memory' and 'devices', while recommended extra controllers are
|
|
'cpu', 'freezer' and 'blkio'. The /etc/cgconfig.conf & cgconfig
|
|
init service used to mount cgroups at host boot time. To manually
|
|
mount them use:
|
|
</p>
|
|
|
|
<pre>
|
|
# mount -t cgroup cgroup /dev/cgroup -o cpuacct,memory,devices,cpu,freezer,blkio
|
|
</pre>
|
|
|
|
<p>
|
|
NB, the blkio controller in some kernels will not allow creation of nested
|
|
sub-directories which will prevent correct operation of the libvirt LXC
|
|
driver. On such kernels, it may be necessary to unmount the blkio controller.
|
|
</p>
|
|
|
|
|
|
<h2>Environment setup for the container init</h2>
|
|
|
|
<p>
|
|
When the container "init" process is started, it will be given several useful
|
|
environment variables.
|
|
</p>
|
|
|
|
<dl>
|
|
<dt>LIBVIRT_LXC_NAME</dt>
|
|
<dd>The name assigned to the container by libvirt</dd>
|
|
<dt>LIBVIRT_LXC_UUID</dt>
|
|
<dd>The UUID assigned to the container by libvirt</dd>
|
|
<dt>LIBVIRT_LXC_CMDLINE</dt>
|
|
<dd>The unparsed command line arguments specified in the container configuration</dd>
|
|
</dl>
|
|
|
|
|
|
<h3>Example config version 1</h3>
|
|
<p></p>
|
|
<pre>
|
|
<domain type='lxc'>
|
|
<name>vm1</name>
|
|
<memory>500000</memory>
|
|
<os>
|
|
<type>exe</type>
|
|
<init>/bin/sh</init>
|
|
</os>
|
|
<vcpu>1</vcpu>
|
|
<clock offset='utc'/>
|
|
<on_poweroff>destroy</on_poweroff>
|
|
<on_reboot>restart</on_reboot>
|
|
<on_crash>destroy</on_crash>
|
|
<devices>
|
|
<emulator>/usr/libexec/libvirt_lxc</emulator>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
</interface>
|
|
<console type='pty' />
|
|
</devices>
|
|
</domain>
|
|
</pre>
|
|
|
|
<p>
|
|
In the <emulator> element, be sure you specify the correct path
|
|
to libvirt_lxc, if it does not live in /usr/libexec on your system.
|
|
</p>
|
|
|
|
<p>
|
|
The next example assumes there is a private root filesystem
|
|
(perhaps hand-crafted using busybox, or installed from media,
|
|
debootstrap, whatever) under /opt/vm-1-root:
|
|
</p>
|
|
<p></p>
|
|
<pre>
|
|
<domain type='lxc'>
|
|
<name>vm1</name>
|
|
<memory>32768</memory>
|
|
<os>
|
|
<type>exe</type>
|
|
<init>/init</init>
|
|
</os>
|
|
<vcpu>1</vcpu>
|
|
<clock offset='utc'/>
|
|
<on_poweroff>destroy</on_poweroff>
|
|
<on_reboot>restart</on_reboot>
|
|
<on_crash>destroy</on_crash>
|
|
<devices>
|
|
<emulator>/usr/libexec/libvirt_lxc</emulator>
|
|
<filesystem type='mount'>
|
|
<source dir='/opt/vm-1-root'/>
|
|
<target dir='/'/>
|
|
</filesystem>
|
|
<interface type='network'>
|
|
<source network='default'/>
|
|
</interface>
|
|
<console type='pty' />
|
|
</devices>
|
|
</domain>
|
|
</pre>
|
|
|
|
<p>
|
|
In both cases, you can define and start a container using:</p>
|
|
<pre>
|
|
virsh --connect lxc:/// define v1.xml
|
|
virsh --connect lxc:/// start vm1
|
|
</pre>
|
|
and then get a console using:
|
|
<pre>
|
|
virsh --connect lxc:/// console vm1
|
|
</pre>
|
|
<p>Now doing 'ps -ef' will only show processes in the container, for
|
|
instance. You can undefine it using
|
|
</p>
|
|
<pre>
|
|
virsh --connect lxc:/// undefine vm1
|
|
</pre>
|
|
</body>
|
|
</html>
|