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LXC 2.0.0 release announcement

6th of April 2016
The LXC team is very pleased to announce the release of LXC 2.0!


  • All main LXC commands have now been rewritten in C
    • lxc-ls
    • lxc-device
    • lxc-copy
  • New lxc-copy command taking over the role of lxc-clone and lxc-start-ephemeral
  • Much improved support for checkpoint/restore of containers
  • Completely reworked cgroup handling including support for the cgroup namespace
  • The various command line tools are now much more consistent
  • Re-organized storage backend implementation, including addition of a Ceph RBD backend
  • An enormous amount of bugfixes, most of which will be backported to 1.0 and 1.1 over the next few bugfix releases
  • The C API remains backward compatible with previous versions and is released as 1.2

This release was made possible by contributions (720 commits) from a total of 96 contributors.

New configuration options

  • lxc.ephemeral: Controls whether the container is ephemeral and so will be destroyed on shutdown
  • lxc.rebootsignal: Allows to override the signal sent for container reboot
  • lxc.hook.destroy: New hook being called on container destruction
  • lxc.hook.stop: Run in the host context with references to the containers just before namespace teardown
  • lxc.init_uid: Used by lxc-execute to set an alternative user
  • lxc.init_gid: Used by lxc-execute to set an alternative group
  • lxc.monitor.unshare: Allows unsharing the mount namespace prior to running any hook

New features

  • API:
    • API version is 1.2, fully backward compatible with 1.1 and 1.0
    • new symbols:
      • New migrate() symbol as an alternative to checkpoint() using a migrate_opts struct to simplify additions
    • python3
      • Support for passing the storage backend to create()
    • lua
      • Add support for get_ips()
      • Add support for get_interfaces()
      • Add support for rename()
  • Core:
    • cgfsng: New cgroup backend driver for recent Linux kernel
    • cgroup: Partial support for the new cgroup hierarchy
    • cgroup: Support for the cgroup namespace
    • checkpoint: Support checkpoint/restore of default LXC containers
    • checkpoint: Support checkpoint/restore of unprivileged containers
    • checkpoint: Support for the page server
    • config: lxc.aa_profile: Now supports an "unchanged" value
    • config: lxc.init_cmd: Now supports arguments
    • config: Added support for the "passthru" mode
    • config: lxc.rootfs.backend: Allows to override the storage backend (bypasses auto-detection)
    • config: New nesting.conf configuration file to setup container nesting
    • hooks: New LXC_CGNS_AWARE environment variable, set to 1 if LXC supports the cgroup namespace (the kernel however may not)
    • hooks: New LXC_SRC_NAME environment variable is set in clone hook with the original container name
    • hooks: New LXC_TARGET environment variable is set with the container goal (stop or reboot)
    • logging: Updated logging timestamps to be a bit more readable
    • lxc-usernet: Support for containers usning a veth interface without bridging
    • lxc-usernet: Support for group-based quotas (use the @ prefix)
    • network: The bridge interface MTU is now used as the default container interface MTU
    • start: The process title is now renamed to be easier to read
    • storage: New Ceph RBD storage backend
  • Documentation:
    • Korean translation of all the man pages
  • Commands:
    • lxc-attach: Use an intermediate pts device to prevent attacks against the parent shell
    • lxc-clone: Support for renaming containers
    • lxc-start-ephemeral: Support for changing bind-mount targets
  • Init systems:
    • systemd: Support for instanced service units
  • Templates
    • New ALTLinux template
    • New Slackware template
    • New SPARCLinux template
    • alpine: Support installing extra packages
    • debian: Default to just "main" enabled, allow enabling other repositories through argument
    • oracle: Set the timezone in the container
    • openssh: Add OpenSSH support
    • ubuntu: New -v option allowing the user to set the debootstrap variant
    • ubuntu-cloud: Support for vendor-data passthrough

Change in behavior

  • The lxc-autostart container startup order is now reversed (to be correct)
  • The new cgfsng cgroup backend is now the recommended backend
  • failures are now fatal to container reboots

Note that several commands have been significantly reworked in this release.
We don't consider our command line tools as stable ABI so you may need to test and adapt your scripts,
or better, port them to use our stable C API or one of its bindings.

Deprecation warnings

The "lxc-clone" and "lxc-start-ephemeral" commands are now considered deprecated and to be replaced by the new lxc-copy.
Those commands can still be built by using the --enable-legacy flag, however note that they will print a warning when used
and that they will be removed from upcoming LXC releases.


This is the second LXC Long Term Support release which we will be supporting until the 1st of June 2021.
LXC 1.0, our previous Long Term Support release, is still supported until the 1st of June 2019.
And lastly, the previous stable release, LXC 1.1 will go end of life on the 1st of September 2016.


The release tarballs may be found on our download page and we expect most distributions
will very soon ship a packaged version of LXC 2.0.0.

Should you be interested in individual changes or just looking at the detailed development history,
our master branch is on GitHub.