[CRIU] Adding checkpoint/restore support to podman question

[Andrei Vagin]

Hi Adrian,

Sorry for the late response. I think we already discussed this scheme
and decided that we need to add support for "external" net namespaces.

If you want, I can implement a criu part. Let me know if you will have
any other questions.

Thanks,
Andrei

On Fri, Apr 06, 2018 at 05:50:49PM +0200, Adrian Reber wrote:
> Currently I am trying to add checkpoint/restore support to podman:
> 
> https://github.com/projectatomic/libpod/pull/469
> 
> The good thing is, the basic functionality works. Right now I am trying
> to setup the network in podman to place the restored processes in a
> container with the same IP and I am confused by the network namespace.
> 
> I see CRIU has '--empty-ns' and '--join-ns' but I am not sure what is
> needed and correct.
> 
> My plan was to let podman set up a new network namespace with the same
> IP. That works. After restore I can ping the IP of the restored
> container, but the restored processes are now in a different namespace
> according to proc. So now I have the network namespace podman created
> with a working IP address and I have the network namespace which
> probably CRIU created during restore.
> 
> So right now I am confused at which levels the network namespace has to
> be handled. At podman or at runc, which is called by podman? Or at
> CRIU's level? Or do I tell CRIU to ignore the network namespace during
> checkpoint or restore?
> 
> If anybody has an idea what the right steps are to restore the network
> setup correctly that would be great! Thanks.
> 
> 		Adrian