LXC

Revision 21 as of 2012-06-09 04:18:30

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Overview

LinuX Containers (LXC) provide lightweight virtualization that lets you isolate processes and resources without the need to provide instruction interpretation mechanisms and other complexities of full virtualization.

Notes

  • Upstream libvirt support LXC.
  • KVM + LXC can function properly on same host.
  • LXC inside KVM works properly on same host.
  • LXC take advantage of KMS feature of new Kernels.
  • 64bit OS using a 32bit container.
  • LXC works well with btrfs.
  • No special hardware required.
  • No patch is required to the kernel, since LXC is already integrated into the Kernel.
  • OpenVZ Containers run on LXC, only Config modification required.

Use case examples

  1. Isolate individual processes (e.g. a webserver)
  2. VPS
  3. LTSP
  4. Software build, testing, upgrading (think sandboxing)

Host configuration

External link - lxc-tools collection of utility scripts which include:

  1. lxc-ubuntu - installs ubuntu container
  2. init - init.d script
  3. lxc-status - lxc-info on all the containers
  4. lxc-halt - stop a linux container SAFELY

External link - How to Ubuntu 10.04 LXC containers

External link - Ubuntu and Fedora Hosts

kernel requirements

The Linux container capabilities are part of the main stream linux kernel and require kernel version >= 2.6.27 (well working as of 2.6.31).

There are no requirements to compile a kernel or apply patches.

User space tools (lxc)

The user space tools, or lxc, are a set of scripts that manage linux containers.

You may install the lxc user space tools from the Ubuntu repositories. 

sudo apt-get install lxc vlan bridge-utils python-software-properties screen

Or download the latest stable package from sourceforge and compile them yourself. The lxc project maintains a git repository for a bleeding edge set of tools.

Networking

There are several networking options available, the consensus appears to be that bridging your network card is the best option. As such I will cover bridging your network card here, hopefully this information can be expanded.

Container configuration

options/examples for config files chroot/debootstrap/febootstrap lxc-debian / lxc-fedora lxc-console / ssh into containers

Migrate OpenVZ containers

Application configuration

Issues

“mknod: `/lib/udev/devices/ppp’: Operation not permitted” when updating Ubuntu 10.04 on virtual LXC machine http://www.emanuelis.eu/2010/09/15/mknod-lib-udev-devices-ppp-operation-not-permitted-when-updating-ubuntu-10-04-on-virtual-lxc-machine/

Other

Mini screen how-to

List screen sessions: 

[HW] # sudo screen -ls
There are screens on:
        1407.init-ubuntu        (07/10/2010 02:23:42 PM)        (Detached)
        1364.init-test  (07/10/2010 02:23:41 PM)        (Detached)
        1357.init-2www  (07/10/2010 02:23:40 PM)        (Detached)
3 Sockets in /var/run/screen/S-root.

Login screen session: 

[HW] # screen -r 1407.init-ubuntu
Starting nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
configuration file /etc/nginx/nginx.conf test is successful
nginx.

Ubuntu 10.04 LTS ubuntu /dev/console

ubuntu login:

Detach screen: C-a d or C-a C-d

source

lxc.network.type=phys & kernel versions

The problem: 

[HW] # lxc-execute --name ubuntu -s lxc.network.type=phys bash
Segmentation fault (core dumped)

or 

[HW] # lxc-execute --name net -s lxc.network.type=phys -s lxc.network.link=eth0 bash
lxc-execute: failed to move 'eth0' to the container : Message too long

The kernel before 2.6.35 does not support physical interface moving across namespace. Maybe You can use Maverck 2.6.35 kernel in Lucid, see: PPA for Ubuntu Kernel

source1 source2

See also

CategoryInstallation CategorySystem