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

[Pavel Emelyanov]

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 . 

Similar thing can be done for external (bind)mounts. Does it make
sense for you?

> -serge

Thanks,
Pavel