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Comment: document creating a new lxc in wheezy
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cgroup /sys/fs/cgroup cgroup defaults 0 0 | cgroup /sys/fs/cgroup cgroup defaults 0 0 |
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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/
LXC is available starting with Debian 5.0 - Lenny (Kernel 2.6.26), however the LXC userspace tools are not packaged for Lenny, so they would have to be built from source. Debian 6.0 - Squeeze has full support for LXC.
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 .
RootFS creation
Debian 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 myfirstcontainer -t squeeze
Debian Wheezy
lxc-create -n myfirstcontainer -t debian
This will prompt you on what distribution to install.
Setup networked containers
Create a bridge on the host (natted/routed), /SimpleBridge
VLAN + bridge setup description, see /VlanNetworking
Use libvirt package for easy network setup (/LibVirtDefaultNetwork)
Start and stop containers
- To start a container and stay attached to the console run:
lxc-start -n myfirstcontainer
- To start a container in the background and attached to the console at any time later run:
lxc-start -n myfirstcontainer -d lxc-console -n myfirstcontainer
- To halt a container cleanly by the containers initv-system:
lxc-halt -n myfirstcontainer
- To stop a container without proper halt inside the container:
lxc-stop -n myfirstcontainer
To have containers automatically started on booting the host, edit the host's /etc/default/lxc
References
See also :
http://blog.rot13.org/2010/03/lxc-watchdog_missing_bits_for_openvz_-_linux_containers_migration.html which describes a tool that allows controlling the guest's startup/shutdown through power signals, and also some more setup for consoles.
Known bugs and "got to know issues"
600466 - "Respawning too fast" messages due to missing tty(1234) nodes in generated container rootfs (workaround: remove from container's /etc/inittab}} or {{{mknod -m 660 dev/tty1 c 5 1 for each device)
See also
SystemVirtualization alternatives