[lxc-users] LXC, criu and cgroups...

[Tycho Andersen]

Hi Dirk,

On Tue, Apr 07, 2015 at 09:03:30PM +0200, Dirk Geschke wrote:
> Hi Tycho,
> 
> I'm now one step ahead, I head a file 00-lxcfs.conf from playing
> around with lxcfs. But this one is not needed with lxc-1.1.x
> As a consequence, cgroup was bind-mounted twice in the container.
> 
> Now at least lxc-checkpoint does not have a problem with the
> mounts of cgroup. Now I end up with:
> 
>    Command "save" is unknown, try "ip addr help".
>    Error (util.c:580): exited, status=255
>    Error (net.c:420): IP tool failed on addr save
>    Error (namespaces.c:802): Namespaces dumping finished with error 65280
>    Error (cr-dump.c:1979): Dumping FAILED.
> 
> Sounds like ip is missing the save option for addr. Maybe the 
> namespace-error is a follow up.
> 
> Ah, with a recompiled package iproute2 from jessie on wheezy this 
> seems to work.
> 
> So I can now checkpoint an unprivileged container on debian wheezy
> with lxc-checkpoint. But still no luck with LXD so far, it is still
> complaining:
> 
>    Found cgmanager mapping for ./sys/fs/cgroup/cgmanager mountpoint
>    Found cgmanager mapping for ./sys/fs/cgroup/cgmanager mountpoint
>    Error (mount.c:636): 92:./sys/fs/cgroup/cgmanager is overmounted

I guess you have lxcfs installed? We currently can't checkpoint
containers with lxcfs, exactly because of this overmounting issue. If
you `sudo apt-get remove lxcfs` and restart the container, does
checkpointing work?

Tycho

> And there is no 00-lxcfs.conf on this system. In the container I
> can see two cgroup mounts:
> 
>    cgroup                       4       0         4   0% /sys/fs/cgroup
>    cgroup                      12       0        12   0% /sys/fs/cgroup/cgmanager
> 
> This is similar to the non-LXD case.
> 
> So actually I'm a little bit clueless here...
> 
> Best regards
> 
> Dirk
> 
> -- 
> +----------------------------------------------------------------------+
> | Dr. Dirk Geschke       / Plankensteinweg 61    / 85435 Erding        |
> | Telefon: 08122-559448  / Mobil: 0176-96906350 / Fax: 08122-9818106   |
> | dirk at geschke-online.de / dirk at lug-erding.de  / kontakt at lug-erding.de |
> +----------------------------------------------------------------------+
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