[lxc-devel] lxc-checkpoint error

[Tycho Andersen]

Hi Ruslan,

On Tue, Mar 24, 2015 at 10:14:02AM +0200, Ruslan Kuprieiev wrote:
> Hi Axel,
> 
> On 03/24/2015 01:17 AM, Axel Schöner wrote:
> >Am Montag, 23. März 2015, 15:42:47 schrieb Ruslan Kuprieiev:
> >>Hi!
> >>
> >>I'm trying to use lxc-checkpoint to dump/restore simple lxc container.
> >>
> >>I added:
> >>|# hax for criu
> >>
> >>lxc.console = none
> >>lxc.tty = 0
> >>lxc.cgroup.devices.deny = c 5:1 rwm|
> >>
> >>to container config, but when I'm trying to run
> >>
> >>|lxc-checkpoint -n $name -D $checkpoint_dir -s -v|
> >>
> >>I get:
> >>Error (mount.c:624): 113: ./sys/fs/cgroup/perf_event doesn't have a
> >>proper root mount
> >The problem is, that "/sys/fs/cgroup/perf_event" is in your case a bindmount
> >from outside (host).
> >CRIU can dump extern ressources which are bind mounted, you can find details
> >on: http://www.criu.org/External_bind_mounts.
> >lxc-checkpoint does not care about /sys/fs/cgroup/perf_event.
> 
> Thanks for a hint.
> 
> But shouldn't lxc-checkpoint just work? I mean, it should dump/restore lxc
> container, so it probably should handle perf_event too.

Unfortunately, the recent autodev patches have broken lxc-checkpoint.
I'm working on some patches to criu to properly resolve mount points as
autodev does them, but I haven't gotten anything working yet.

Another problem is that systemd mounts propagate differently (SLAVE vs
PRIVATE), and that confuses criu as well. I'm now back focused more on
migration/criu vs LXD proper, so fixes should be rolling in in the
coming weeks, hopefully.

That said, can you show /proc/<pid>/mountinfo for init? It looks like
your cgroups may be mounted in yet another configuration that we're
not prepared to handle that I haven't seen before.

Thanks,

Tycho

> >
> >
> >
> >>Could you give me a hint on what is going on?
> >>I also saw that other people do experience the same problem:
> >>http://tycho.ws/blog/2014/09/container-migration.html
> >>
> >>Thanks,
> >>Ruslan
> Thanks,
> Ruslan
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