[Lxc-users] Container start unmounts shared bind mounts

Ivan Vilata i Balaguer ivan at selidor.net
Thu Feb 9 17:32:03 UTC 2012

Hi all.  I'm running Debian's LXC 0.7.5 under Linux 3.2.0.  I've set up
a shared mountpoint to dynamically export some host directories into one
container, like this::

  # mkdir -p /lxc-shared
  # mount --bind /lxc-shared /lxc-shared
  # mount --make-unbindable /lxc-shared
  # mount --make-shared /lxc-shared

Now I bind mount the host directory under the shared directory::

  # mkdir -p /lxc-shared/myvm/foo
  # mount --bind /tmp /lxc-shared/myvm/foo

The problem is that whenever I start any container, /lxc-shared/myvm/foo
gets unmounted (even if it has processes working under it!).  This
affects bind mounts only if they are under shared mountpoints, e.g. if I
also do this mount on the host::

  # mount --bind /tmp /mnt

It survives after starting the container.

Does anyone know why does this happen?  Should I file a bug report?
Thanks a lot!
Ivan Vilata i Balaguer -- https://elvil.net/

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