[CRIU] Live migration of LXC containers using Criu?

[Kir Kolyshkin]

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.

This is as much as I can tell without looking into speciifics.

Regards,
   Kir.

>
> Thanks,
> Divjyot
>
> On Tue, Apr 28, 2015 at 1:15 AM, Pavel Emelyanov <xemul at parallels.com 
> <mailto:xemul at parallels.com>> wrote:
>
>     On 04/27/2015 10:43 PM, Divjyot sethi wrote:
>     > Hey Pavel,
>     > I have been trying to setup OpenVZ on fedora 20 as you had advised for the past few days. I
>     > was able to create a container and start it. However, I am
>     unable to enter the container
>     > (gives error: /Directory /proc/vz not found, assuming non-OpenVZ
>     kernel
>     > enter into CT 1002 failed
>     > Unable to open pty: No such file or directory/).
>
>     Yes, entering for Fedora kernel doesn't work. You can ssh into
>     container instead,
>     the [1] article describes how to setup networking for container to
>     make it
>     migrate-able.
>
>     [1]
>     https://github.com/xemul/p.haul/wiki/Configuring-network-for-OpenVZ-container
>
>     > I tried the instructions on
>     /http://wiki.openvz.org/Container_enter_failed/, and,
>     > /https://openvz.org/Vzctl_for_upstream_kernel/ but no luck.
>     Since this is an upstream kernel
>     > - not sure if there are any patches available for this? (I have been booting regular kernel).
>     >
>     > Can you please help me with setting this up? Also, did you patch
>     your kernel? Were you able
>     > to enter the container or you just ssh to it instead?
>
>     Entering openvz container only works for patched kernel. But for
>     patched kernel
>     there's still no criu support :( But openvz kernel guys are
>     working on it.
>
>     > Finally, not sure if this question is apt for this mailing list?
>     > If not, is there an alternate mailing list to which I can email?
>
>     Well, for openvz-related questions the devel at openvz.org
>     <mailto:devel at openvz.org> is good place to start, but
>     for C/R and live migration questions it's better to at least Cc:
>     criu@ mailing list.
>
>     > Thanks for your help!
>     > Divjyot
>
>     -- Pavel
>
>

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