[lxc-users] Live migration mkdtemp failure

[Tycho Andersen]

On Tue, Jun 21, 2016 at 09:27:21AM -0700, jjs - mainphrame wrote:
> That particular error was resolved, but the lxc live migration doesn't work
> for a different reason now. We now get an error that says "can't dump ghost
> file" because of apparent size limitations - a limit less than the size of
> any lxc container we have running here.

How big is the ghost file that you're running into and what
application is it from? Perhaps we should just increase the default
limit.

Tycho

> (In contrast, live migration on all of our Openvz 7 containers works
> reliably)
> 
> Jake
> 
> 
> 
> 
> On Tue, Jun 21, 2016 at 4:19 AM, McDonagh, Ed <Ed.McDonagh at rmh.nhs.uk>
> wrote:
> 
> >
> >
> > > On Tue, Mar 29, 2016 at 09:30:19AM -0700, jjs - mainphrame wrote:
> > > > On Tue, Mar 29, 2016 at 7:18 AM, Tycho Andersen <
> > > > tycho.andersen at canonical.com> wrote:
> > > >
> > > > > 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?
> > >
> > > It already is enabled, you can find the full logs in
> > > /var/log/lxd/$container/migration_*
> > >
> > > Perhaps the pwd of the CRIU task is what's broken instead, since CRIU
> > > isn't supplying a full mkdtemp template. I'll have a deeper look in a
> > > bit.
> > >
> > > Tycho
> > >
> > > >
> > > > > >
> > > > > > root at ronnie:~# lxc move third lxd:
> > > > > > error: Error transferring container data: restore failed:
> > > > > > (00.033172)      1: Error (cr-restore.c:1489): mkdtemp failed
> > > > > > crtools-proc.x9p5OH: Permission denied
> > > > > > (00.060072) Error (cr-restore.c:1352): 9188 killed by signal 9
> > > > > > (00.117126) Error (cr-restore.c:2182): Restoring FAILED.
> >
> > I've been getting the same error - was the issue ever resolved for
> > non-privileged containers?
> >
> > Kind regards
> > Ed
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