[Lxc-users] lxc on fedora 15 (was : cgroups: support cgroups mounted in multiple places)

[Daniel Lezcano]

On 06/24/2011 07:54 PM, Serge Hallyn wrote:
> I.e. with systemd or libcgroup.
>
> To do this, instead of looking for one cgroup called 'lxc' or
> otherwise taking the first cgroup we find, we actually create a
> container in every mounted cgroup fs.  Right now it's done under the
> root of each fs.  We may want to put that under lxc, or, better yet,
> make that configurable.
>
> Note the use of clone_children seems not quite right, but that's
> not for this patch to fix.  In particular, if clone_children is
> not in the mntopts, we reject it.  Yet later we try to set it
> ourselves.  I believe we should simply, if ns cgroup is not
> composed, always try to set clone_children to 1.  As it stands,
> with libcgroup installed, I had to do
>
>    cd /sys/fs/cgroup
>    for d in `/bin/ls`; do
>       echo 1 > $d/cgroup.clone_children
>    done
>
> But after that, 'lxc-start -n l1' worked like a charm.  It also
> continues to work with a single mount of cgroups under /cgroup.
>
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
> ---

fedora 15 has a patched kernel with utrace.

Are we sure, utrace is pid namespace aware ?

My natty container booted on fedora 15 but is stuck at:

\_ lxc-start -n natty -l DEBUG -o /dev/pts/0
    \_ /sbin/init
        \_ /sbin/plymouthd --mode=boot --attach-to-session
            \_ /sbin/plymouthd --mode=boot --attach-to-session


pidof /sbin/plymouthd
6224 6222

cat /proc/6224/stack
[<ffffffff81098ad9>] utrace_stop+0x128/0x181
[<ffffffff81098b9c>] finish_resume_report+0x6a/0xb2
[<ffffffff810999ea>] utrace_get_signal+0x460/0x5a6
[<ffffffff81064d0a>] get_signal_to_deliver+0x102/0x3a9
[<ffffffff81008f43>] do_signal+0x69/0x67f
[<ffffffff8100959a>] do_notify_resume+0x28/0x83
[<ffffffff81009e90>] int_signal+0x12/0x17
[<ffffffffffffffff>] 0xffffffffffffffff

cat /proc/6222/stack
[<ffffffff8112882d>] pipe_wait+0x61/0x7c
[<ffffffff81128fe6>] pipe_read+0x344/0x3c1
[<ffffffff811212b2>] do_sync_read+0xbf/0xff
[<ffffffff81121919>] vfs_read+0xa9/0xf0
[<ffffffff811219aa>] sys_read+0x4a/0x6e
[<ffffffff81009bc2>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff