[Lxc-users] CPU cgroup starts by itself

[Fajar A. Nugraha]

On Thu, Mar 15, 2012 at 7:44 PM, Goran Cetusic <goran.cetusic at gmail.com> wrote:
> I have problems with starting containers in Linux Mint Debian Edition
> because /dev/cgroup/cpu is mounted by itself.
>
> lxc-start: cgroup is not mounted
> lxc-start: failed to setup the cgroups for 'imunes'
> lxc-start: failed to setup the container
> lxc-start: invalid sequence number 1. expected 2
> lxc-start: failed to spawn 'imunes'
>
> I realize it's not mounted because I didn't mount...because I can't!
> I believe this generates the following error when trying to mount cgroups
>
> $ mount none -t cgroup /cgroup
> mount: none already mounted or /cgroup busy
>
> It's not in fstab so I have no idea what is mounting it.
> Any suggestions on
>
> A) How to solve the current mount problem?
> B) What is mount the cgroup?

Not sure about mint (I don't use it), but Ubuntu has /lib/init/fstab:

# /lib/init/fstab: static file system information.
#
# These are the filesystems that are always mounted on boot, you can
# override any of these by copying the appropriate line from this file into
# /etc/fstab and tweaking it as you see fit.  See fstab(5).

While in ubuntu it does NOT mount cgroup, mint might use something like that.

Also, in ubuntu there's /etc/init/cgconfig.conf, which IS responsible
for mounting cgroup. In my experince it doesn't work very well. Or
rather, it STARTS very well, but once I add cpuset to
/etc/cgconfig.conf, it won't to stop cleanly. So I override it with my
own mount/umount commands. A similar upstart/service/inittab might do
the same on mint.

-- 
Fajar