[Lxc-users] Zombie container

[Milan Zamazal]

>>>>> "DL" == Daniel Lezcano <daniel.lezcano at free.fr> writes:

    DL> It is probable you have an application creating new namespaces
    DL> in the container. That's triggering a new cgroup creation which
    DL> is nested with the container's one. This is a kernel feature
    DL> (removed for the next kernel version).

Thank you for explanation.

By watching when these subdirectories get created I discovered the
problem appears when I run `fusermount -u'.

    DL>   * simply do rm -rf /cgroup/blackbird (don't care about the
    DL>   errors).

This fails with "Operation not permitted" and the problem persists.

    DL> Launch your container and then look at
    DL> /cgroup/blackbird/1234/tasks and look for the command line
    DL> associated with the pid in this file.

The `tasks' file is empty.  But it must be fusermount or something
related to its invocation.

    DL> Hope that helps.

Thank you for help.  Now I know what creates the problem, but I still
don't know how to safely prevent it or remedy it.  Maybe it's a kernel
problem (I use standard kernel 2.6.32 from Debian)?