[CRIU] zdtm with proxy-cache

[Rodrigo Bruno]

On Wed, 10 Feb 2016 16:40:12 -0800
Andrew Vagin <avagin at virtuozzo.com> wrote:

> On Mon, Feb 08, 2016 at 01:56:27AM +0000, Rodrigo Bruno wrote:
> > Hi,
> > 
> > I am testing CRIU with proxy-cache migration (using sockets) using zdtm.py script
> > but I ran into two problems.
> > 
> > 1- I start both the proxy and cache with --pidfile and their pids gets written 
> > into specific files. However, the pids of both processes (proxy and cache) change
> > after getting written and therefore, from zdtm.py, I cannot kill them reading the
> > pidfile. 
> > 
> > I looked into the page-server and it seems to quit before the zdtm.py script 
> > attempts to kill it. If it does not quit, zdtm.py will fail to kill it as well
> > (because the pid inside the pid file is no longer the real one).
> > 
> > Do you know why this happens, why the real pid does not match the pid inside
> > the pidfile?
> 
> Maybe you try to kill a process from another pidns? zdtm_ct creates a
> new pidns.

It is very strange... It happens even if I only test with the host ns.

> > 
> > 2- I cannot run tests using namespaces. I think the problem is related to a 
> > unix socket that is used to communicate between the cache and CRIU Restore.
> > As soon as the restore operation attempts to mount the namespaces, new 
> > connections to the unix socket no longer succeed. 
> 
> It may be due to network namespaces. You need to connect to a cache
> before forking the root task and then always use this socket, because
> the root task will be executed in another set of namespaces.

I am using the cache as a close as possible as a local file system. Therefore
I am creating a connection for each file open request.

I will look if there is any way to reach the cache in the new ns.

Sorry for the long 'construction' of this patch. I'm trying to keep up with
you but haven't had much time :)

> 
> Thanks,
> Andrew
> 
> > 
> > Do you have any idea of a potential reason for this? Where should I look at?
> > 
> > Thanks,
> > Rodrigo Bruno
> > 
> > -- 
> > Rodrigo Bruno <rbruno at gsd.inesc-id.pt>
> > _______________________________________________
> > CRIU mailing list
> > CRIU at openvz.org
> > https://lists.openvz.org/mailman/listinfo/criu


-- 
Rodrigo Bruno <rbruno at gsd.inesc-id.pt>