[lxc-users] lxc progress and a few questions

Fri Apr 8 06:01:06 UTC 2016

(Bump) -

Any thoughts on what to try for the CT migration and dhcp issues?
Running up to date ubuntu 16.04 beta -

Regards,

Jake

On Wed, Apr 6, 2016 at 3:18 PM, jjs - mainphrame <jjs at mainphrame.com> wrote:
> Greetings -
>
> I'be not yet been able to reproduce that one shining moment from Mar
> 29 when live migration of privileged containers was working, under
> kernel 4.4.0-15
>
> To recap. live container migration broke with 4.4.0-16, and is still
> broken in 4.4.0-17 - but  now, instead of producing an error message,
> an attempt to live migrate a container merely hangs forever. Is that
> expected, or should I be seeing something more? BTW - the migration
> dump log for that container hasn't been touched for a week. I'll be
> glad to supply more info if this is not a known issue.
>
> Recent updates seem to have created a new problem. the CTs which
> configure their own network settings work (aside from migration) but
> none of the CTs which depend on dhcp are getting IPs. BTW I'm using a
> bridge connected to my local network and dhcp, not the default lxc
> dhcp server. I see the packets on the host bridge, but they don't
> reach the dhcp server. I'd be curious to know if there have been any
> dhcp issues since recent updates. If not, I'll need to troubleshoot
> other causes, but it's odd that dhcp simply stops working for all CTs
> on both lxd hosts after updates.
>
> Jake
>
>
> On Wed, Mar 30, 2016 at 6:27 AM, Tycho Andersen
> <tycho.andersen at canonical.com> wrote:
>> On Tue, Mar 29, 2016 at 11:17:26PM -0700, jjs - mainphrame wrote:
>>> 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.
>>
>> Yep, this is a known issue with -16. We need both a kernel patch and a
>> patch to CRIU before it will start working again. I have a branch at:
>>
>> https://github.com/tych0/criu/tree/cgroup-root-mount
>>
>> which should work if you want to keep playing with it, but hopefully
>> we'll have the situation sorted out in the next few days.
>>
>> Tycho
>>
>>> 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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