[lxc-users] after stopping container, mountpoint is still there

[Florian Klink]

Hi,

I have the problem that filesystems mounted with lxc.hook.pre-mount stay
mounted the whole time, even after the container is stopped.

According to my understandinding, mountpoints mounted by these hook
scripts will be private to the container and cleaned up on container
stop automatically (man lxc.container.conf):

lxc.hook.pre-mount
A  hook to be run in the container's fs namespace but before the rootfs
has been set up. This allows for manipulation of the rootfs, i.e. to
mount an encrypted filesystem. Mounts done in this hook will not be
reflected on the host (apart from mounts propagation), so they will be
automatically cleaned up when the container shuts down.



However, I can see them when running `df` or `mount` on the host, and
they stay mounted even when the container is stopped (which creates
weird errors when you try to start the container again).


A bit more information about my setup:

Arch Linux amd64, systemd 211, kernel 3.13.6

I created an archlinux "base image"
(using pacstrap -d /path/to/base-image base base-devel), and union-mount
it together with a cow/ directory to the new root.

The hook looks similar to the provided "hooks/mountecryptfsroot":

mount-aufs:

#!/bin/sh
LXC_COW_PATH=$(echo $LXC_ROOTFS_PATH | sed 's/root$/cow/')
mount -n -t aufs none ${LXC_ROOTFS_PATH} -o br=${LXC_COW_PATH}=rw:$1=ro


container config:

[...]
lxc.autodev = 1
lxc.hook.pre-mount = /var/lib/lxc/container-name/mount-aufs
/path/to/base/image
lxc.rootfs = /var/lxc/containers/container-name/root
[...]



I also tried to hook an lxc.hook.post-stop script that umounts it, but
that's also working not reliable...


Is this intended behaviour or a bug?

Florian