[CRIU] [PATCH 00/11] p.haul: implement migration in so-called revive mode

[Nikita Spiridonov]

On Mon, 2016-03-14 at 13:50 -0400, Christopher Covington wrote:
> On 03/04/2016 04:31 AM, Nikita Spiridonov wrote:
> > Implement so-called revive migration mode which migrate fs to target
> > host iteratively while possible, stop process tree on source host
> > and start it on target host. C/r not used in this mode.
> 
> What do you mean "C/r not used"? How do you start the process tree if
> not by running `criu restore` "r" on a set of images that were created
> by `criu dump` "c"?.
> 

It seems such migration mode relevant exclusively for containers
migration (Virtuozzo, LXC and so on). 

For example, during Virtuozzo container migration in such mode we
migrate disks iteratively to target host, than stop container on source
side, handle final disks sync and start container on targer side. So,
finally, Virtuozzo core is implicitly responsible for process tree
restoration on target host, but actually it is another process tree
(since guest os was restarted).

Such approach decrease downtime in comparison with manual stopping and
starting of container by end user since considerable part of container
fs already transferred to target host when container stopped.

I know that such usage conflicts slightly with initial conception of
p.haul as process hauler, but it help to avoid fs migration code
duplication in other utilities.