[Lxc-users] [PATCH 2/2] cgroups: support cgroups mounted in multiple places

[Daniel Lezcano]

On 06/26/2011 05:06 PM, Serge E. Hallyn wrote:
> Quoting Michael H. Warfield (mhw at WittsEnd.com):
>>> cd /sys/fs/cgroup
>>>    for d in `/bin/ls`; do
>>>       echo 1 > $d/cgroup.clone_children
>>>    done
>>
>> Doing this step alone broke lxc totally for me, with or without the
>> patch below.  This was on Fedora 15 testing with lxc 0.7.4.2 as well as
> 
> Do you have the ns cgroup mounted?  The above is only for without
> ns cgroup.

Yes, the ns_cgroup and clone_children are mutually exclusive.

If you try to create a namespace with a ns cgroup mounted and the
clone_children flag is set. The 'clone' will return EINVAL.

I noticed with the patch applied because there was a bug in it which was
setting this flag even if the cgroup was ns.

It is possible, you ran lxc with the patch, the clone_children was set,
and then you remove the patch and try to run lxc again. As the
clone_children is still set, that will make impossible to clone a new
namespace.

With the patch I sent previously on top of Serge's patch, that should be
fixed.