[CRIU] Live migration of LXC containers using Criu?

[Pavel Emelyanov]

On 06/05/2015 01:02 AM, Divjyot sethi wrote:
> Thanks -- was able to fix it. :) Now another problem. Apparently restore doesnt work on desitination I get an error  saying:
> 1: Error (cgroup.c:907): cg: Can't move into systemd//user.slice/user-1000.slice/session-3.scope/tasks (-1/-1): No such file or directory.

Ah. This is because p.haul doesn't feed the --manage-cgroups option into criu on restore. And, if you're using
the ovz haul driver, tries to mess with cgroups itself, need do rip this piece from p.haul.

> Error (cr-restore.c 1896): Restoring FAILED.
> 
> Seems that this error was in a prior mailing list where you asked to list the cgroups. I did that and it seems that
> session-3.scop doesnt exist in user-1000.slice at destination (exists at source). Is there some way of creating this? The discussion
> in the prioir mailing list doesnt seem to list a solution to this problem...
> 
> Thanks,
> Divjyot
> 
> On Thu, Jun 4, 2015 at 2:36 AM, Pavel Emelyanov <xemul at parallels.com <mailto:xemul at parallels.com>> wrote:
> 
>     On 06/04/2015 04:50 AM, Kir Kolyshkin wrote:
>     >
>     >
>     > On 06/03/2015 06:45 PM, Divjyot sethi wrote:
>     >> Hey Pavel,
>     >> After a bit of a hiatus, I finally got around to istalling everything on my machines and am now trying
>     >> to live migrate OpenVZ containers running CentOS with p.haul. I however get an error at CRIU dump stage
>     >> -- log file says "Error (sk-unix.c:222): Unix socket 0x6893 without peer 0xc5b". Any thoughts on this issue?
>     >
>     > The message essentially means that there is a UNIX socket that has one end inside the container and the
>     > other end out of it. Like, a container is running mysql and someone who's not inside that CT is connected
>     > to it via a UNIX socket. CRIU warns you that if you will checkpoint a process at one end of such a socket,
>     > a process at the other end might get disappointed. In case you know what you are doing, you can add
>     > --ext-unix-sk to criu commandline to allow checkpointing of such processes.
> 
>     Yup. These are connections to the outer world, the --ext-unix-sk should help, unless the
>     connection is SOCK_STREAM. In the latter case you'll have to stop the process that has one.
> 
>     > This is as much as I can tell without looking into speciifics.
> 
>     -- Pavel
> 
>