[Lxc-users] Container failed, can't remove cgroup

[Lars Kellogg-Stedman]

I'm runing LXC 0.7.5 under Fedora 17 (3.7.3-101.fc17.x86_64).  I've been
banging my head against LXC for a bit today.  My latest problem is that
if a container fails to start, I run into this situation:

  # lxc-start -n node0
  lxc-start: Device or resource busy - failed to remove previous cgroup '/sys/fs/cgroup/systemd/node0'
  lxc-start: failed to spawn 'node0'
  lxc-start: Device or resource busy - failed to remove cgroup '/sys/fs/cgroup/systemd/node0'

There does indeed exist a cgroup by this name:

  # find /sys/fs/cgroup -name node0
  /sys/fs/cgroup/systemd/node0

But it has no tasks:

  # cat /sys/fs/cgroup/systemd/node0/tasks 
  #

It does, however, have a number of child cgroups:

  # find /sys/fs/cgroup/systemd/node0/ -type d
  /sys/fs/cgroup/systemd/node0/
  /sys/fs/cgroup/systemd/node0/system
  /sys/fs/cgroup/systemd/node0/system/getty at .service
  /sys/fs/cgroup/systemd/node0/system/getty at .service/tty1
  /sys/fs/cgroup/systemd/node0/system/systemd-logind.service
  /sys/fs/cgroup/systemd/node0/system/dbus.service
  /sys/fs/cgroup/systemd/node0/system/systemd-journald.service
  /sys/fs/cgroup/systemd/node0/system/sys-kernel-config.mount
  /sys/fs/cgroup/systemd/node0/system/dev-hugepages.mount
  /sys/fs/cgroup/systemd/node0/system/sys-kernel-debug.mount
  /sys/fs/cgroup/systemd/node0/system/sys-fs-fuse-connections.mount
  /sys/fs/cgroup/systemd/node0/system/dev-mqueue.mount

I can remove these by hand:

  # find /sys/fs/cgroup/systemd/node0/ -type d | tac | xargs rmdir

...but is there any way to prevent this situation from happening in the
first place?

Thanks,

-- 
Lars Kellogg-Stedman <lars at oddbit.com>