[CRIU] [Lxc-users] Do we have a plan to make the checkpoint/restart feature.

[Andrew Vagin]

On Fri, Dec 06, 2013 at 03:00:05PM -0600, Serge Hallyn wrote:
> Quoting Pavel Emelyanov (xemul at parallels.com):
> > On 12/04/2013 10:12 PM, Serge Hallyn wrote:
> > > Quoting Nipun Arora (nipun at cs.columbia.edu):
> > >> Hi,
> > >>
> > >> I've been tryint criu for checkpointing and restart. One of the issues is
> > >> that criu does not support external console.
> > >> I tried setting lxc.console = none, and lxc.tty = 0... but seem to get no
> > >> progress when I run the following command..
> > >>
> > >> lxc-create -t ubuntu -n test_lxc -f test_config
> > >> lxc-start -n test_lxc
> > >>
> > >> The config file basically has only the following 2 lines
> > >> lxc.console = none
> > >> lxc.tty = 0
> > >>
> > >> Can someone help out in explaining why this is happening?
> > > 
> > > I think it's been explained before - the external console points
> > > to a device file sitting in another mount namespace.  criu can't
> > > checkpoint that.
> > 
> > Ack.
> > 
> > > Back in the in-kernel checkpoint days, IIRC we allowed such files
> > > to be marked as uncheckpointable in the image, and the restart
> > > program to fill those fds in with fds it had opened beforehand.
> > > 
> > > Can that be done with crui?
> > 
> > In theory -- yes. IOW -- we need to patch criu to achieve that. I
> > planned to make this support using plugins to criu that help dumping
> > external mount points. Currently Andrey works on such a plugin for 
> > external unix sockets, you can find his patches on the list From: avagin at . 
> 
> sorry, which list?  :)

Hi Serge,

Andrey, it's me.

Pavel talks about the CRIU mail list
https://lists.openvz.org/mailman/listinfo/criu

Here are my patches about CRIU plugins:
http://lists.openvz.org/pipermail/criu/2013-December/011531.html

Thnaks,
Andrey

> 
> > Similar thing can be done for external (bind)mounts. Does it make
> > sense for you?
> 
> Yes, that sounds good.  And a fast criu-image-grep util which can tell
> the caller (lxc-restore) which fds and mounts and maybe nics the
> image needs filled in.
> 
> -serge
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