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Comment: linux32 trick not working with new template :(
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Comment: Re-order Debian versions because it's confusing
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=== Debian 8 "Jessie"/testing ===

Same as Debian 7 (see below), though if you want to specify the suite or mirror, use environment variables: {{{
SUITE=wheezy MIRROR=http://ftp.fr.debian.org/debian lxc-create -n myvm -t debian
}}}
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}}}

=== Debian Testing "Jessie" ===

Same as Debian 7, though if you want to specify the suite or mirror, use environment variables: {{{
SUITE=wheezy MIRROR=http://ftp.fr.debian.org/debian lxc-create -n myvm -t debian

Translation(s): none


Linux Containers (LXC) provide a Free Software virtualization system for computers running GNU/Linux. This is accomplished through kernel level isolation. It allows one to run multiple virtual units simultaneously. Those units, similar to chroots, are sufficiently isolated to guarantee the required security, but utilize available resources efficiently, as they run on the same kernel.

For all related information visit : http://lxc.sourceforge.net/

Full support for LXC (including userspace tools) is available since the Debian 6.0 "Squeeze" release.

Current issues in Debian 7 "Wheezy":

You can also read some sub pages :

Installation

  • Install required packages

aptitude install lxc
  • Install optional packages

aptitude install bridge-utils libvirt-bin debootstrap

Prepare the host

  • Required: Mount cgroup reboot save (since 595964 /sys/fs/cgroup is prepared to mount cgroup, see also 601757)

Add this line to /etc/fstab

cgroup  /sys/fs/cgroup  cgroup  defaults  0   0

Try to mount it (a reboot solves an eventual "resource busy problem" in any case)

mount /sys/fs/cgroup
  • Optional: Enable memory cgroup support (534964) (CONFIG_CGROUP_MEM_RES_CTLR) - Since 2.6.39-bpo60-2 for Squeeze the memory cgroup support is built in, so lxc-checkconfig will give you a green result about this point. At the same time, it is deactivated by default. You need to activate memory cgroup support with a kernel parameter. When using grub2, this can be easily done by adding GRUB_CMDLINE_LINUX="cgroup_enable=memory" in /etc/default/grub and running update-grub2. Same for CONFIG_CGROUP_MEM_RES_CTLR_SWAP - see http://lists.debian.org/debian-kernel/2012/01/msg00804.html .

Check kernel configuration :

# lxc-checkconfig 
Kernel config /proc/config.gz not found, looking in other places...
Found kernel config file /boot/config-2.6.32-5-amd64
--- Namespaces ---
Namespaces: enabled
Utsname namespace: enabled
Ipc namespace: enabled
Pid namespace: enabled
User namespace: enabled
Network namespace: enabled
Multiple /dev/pts instances: enabled

--- Control groups ---
Cgroup: enabled
Cgroup namespace: enabled
Cgroup device: enabled
Cgroup sched: enabled
Cgroup cpu account: enabled
Cgroup memory controller: missing
Cgroup cpuset: enabled

--- Misc ---
Veth pair device: enabled
Macvlan: enabled
Vlan: enabled
File capabilities: enabled

Note : Before booting a new kernel, you can check its configuration
usage : CONFIG=/path/to/config /usr/bin/lxc-checkconfig

Here, I've Cgroup memory controller: missing. If you want memory control via cgroups then the Kernel recompilation is needed.

RootFS creation

Debian 8 "Jessie"/testing

Same as Debian 7 (see below), though if you want to specify the suite or mirror, use environment variables:

SUITE=wheezy MIRROR=http://ftp.fr.debian.org/debian lxc-create -n myvm -t debian

Debian 7 "Wheezy"

LXC installs correctly on Wheezy (including a working Debian template since 7.4).

Use:

lxc-create -n myvm -t debian

which will prompt you on what distribution to install.

Then adapt network configuration in /var/lib/lxc/myvm/config, e.g. to plug it on libvirt's bridge:

lxc.utsname = myvm
lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = virbr0
lxc.network.ipv4 = 0.0.0.0/24
lxc.network.hwaddr = 00:1E:62:CH:NG:ME

Other templates can be downloaded, before 7.4 we recommended the one referenced on the LXC container mailing list:

lxc-create -n myvm -t debian-wheezy
# or for a 32-bit container:
linux32 lxc-create -n myvm -t debian-wheezy

Debian 6.0 "Squeeze"

  • In theory you may use any tool to create a rootfs (debootstrap, multistrap, rootstock) as long as you are sure, that the result will run inside a container.
  • For the first time and as an example, use the provided creation script of the lxc package.

cp -a /usr/lib/lxc/templates/lxc-debian /usr/lib/lxc/templates/lxc-squeeze
  • (lxc-debian is designed to install lenny, which is no longer accessible from the specified archive.) Edit lxc-squeeze, replacing "lenny" with "squeeze" and "dhcp-client" with "isc-dhcp-client"

lxc-create -n myvm -t squeeze -f /usr/share/doc/lxc/examples/lxc-veth.conf
  • Here, we use lxc-veth.conf config file

Setup networked containers

Start and stop containers

Notes/warnings on starting and stopping containers:

  • When you connect to a container console, lxc will let you know how to quit it. The first time you log in however, getty will clear the screen, so you'll probably miss this bit of information:

    Type <Ctrl+a q> to exit the console, <Ctrl+a Ctrl+a> to enter Ctrl+a itself
  • If you're using screen and also use the Ctrl+a command prefix, type <Ctrl+a a q> to exit the console.

  • <!> When you start the container in foreground mode (without -d), there's apparently no way to quit the terminal (<Ctrl+a q> doesn't work). Make sure you start the containers in background mode with -d, unless you need to debug why a container didn't start.

  • lxc-halt yields telinit: timeout opening/writing control channel /run/initctl - instead, do a 'poweroff' inside the container, and finish it off with lxc-stop. Alternative work-around: use lxc.cap.drop = sys_admin in the container config file.

Actual commands:

  • To start a container in the background and attached to the console at any time later run (by default, login/password is root/root):

    lxc-start -n myvm -d
    lxc-console -n myvm
  • To start a container in foregroup mode and stay attached to the console run (see warning above):

    lxc-start -n myvm
  • To halt a container cleanly by the containers initv-system (see timeout note above):

    lxc-halt -n myvm
  • To stop a container without proper halt inside the container:

    lxc-stop -n myvm
  • To have containers automatically started on booting the host, link their config file in /etc/lxc/auto/:

    ln -s /var/lib/lxc/mycontainer/config /etc/lxc/auto/mycontainer

Bind mounts inside the container

By default only the container's filesystem is mounted inside the container (even if on the host, /var/lib/lxc/mycontainer/rootfs has other mount points).

To mount another filesystem in the container, add to /var/lib/lxc/mycontainer/config:

lxc.mount.entry=/path/in/host/mount_point /var/lib/lxc/mycontainer/rootfs/mount_moint none bind 0 0

and restart the container. The mount point will now be visible inside the container as well.

Both paths can be identical if necessary.

Support

References

See also :

Known bugs and "got to know issues"

  • 600466 - "Respawning too fast" messages and can't connect to console due to missing tty(1234) nodes in generated container rootfs. Workaround: remove from container's /etc/inittab or start container in interactive mode and mknod -m 660 dev/tty1 c 5 1 for each required tty.

  • Some bugs that might apply to non-official containers - read the follow-ups for solutions.

See also