[lxc-users] lxc progress and a few questions

[jjs - mainphrame]

Well, I've found some interesting things here today. I created a couple of
privileged xenial containers, and sure enough, I was able to live migrate
them back and forth between the 2 lxd hosts.

So far, so good.

Then I did an apt upgrade - among the changes was a kernel change from
 4.4.0-15 to 4.4.0-16 - and live migration stopped working.

Here are the failure messages that resulted from attempting the very same
live migrations that worked before the upgrade and reboot into 4.4.0-16:

root at raskolnikov:~# lxc move akira lxd2:
error: Error transferring container data: checkpoint failed:
(00.092234) Error (mount.c:740): mnt: 83:./sys/fs/cgroup/devices doesn't
have a proper root mount
(00.098187) Error (cr-dump.c:1600): Dumping FAILED.


root at ronnie:~# lxc move third lxd:
error: Error transferring container data: checkpoint failed:
(00.076107) Error (mount.c:740): mnt: 326:./sys/fs/cgroup/perf_event
doesn't have a proper root mount
(00.080388) Error (cr-dump.c:1600): Dumping FAILED.

Jake

PS - Thanks for the html mail heads-up - I've been using google mail
services for this domain. I'll have to look into the config options, and
see if I can do the needful.


On Tue, Mar 29, 2016 at 12:45 PM, Andrey Repin <anrdaemon at yandex.ru> wrote:

> Greetings, jjs - mainphrame!
>
> >> On Mon, Mar 28, 2016 at 08:47:24PM -0700, jjs - mainphrame wrote:
>  >>> I've looked at ct migration between 2 ubuntu 16.04 hosts today, and
> had
>  >>> some interesting problems;  I find that migration of stopped
> containers
>  >>> works fairly reliably; but live migration, well, it transfers a lot of
>  >>> data, then exits with a failure message. I can then move the same
>  >>> container, stopped, with no problem.
>  >>>
>  >>> The error is the same every time, a failure of "mkdtemp" -
> >>
> >>  It looks like your host /tmp isn't writable by the uid map that the
> >>  container is being restored as?
>
>
> > Which is odd, since /tmp has 1777 perms on both hosts, so I don't see how
> > it could be a permissions problem. Surely the default apparmor profile is
> > not the cause? You did give me a new idea though, and I'll set up a test
> > with privileged containers for comparison. Is there a switch to enable
> verbose logging?
>
> I've ran into the same issue once. Stumbled upon it for nearly a month,
> falsely
> blaming LXC.
> Recreating a container's rootfs from scratch resolved the issue.
> I know not of what caused it to begin with, must've been some kind of
> glitch.
>
> P.S.
> It would be great if you can configure your mail client to not use HTML
> format
> for lists.
>
>
> --
> With best regards,
> Andrey Repin
> Tuesday, March 29, 2016 22:43:04
>
> Sorry for my terrible english...
> _______________________________________________
> lxc-users mailing list
> lxc-users at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-users
>
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