On 05/29/2014 01:54 PM, Richard Weinberger wrote: > Am 29.05.2014 11:41, schrieb Pavel Emelyanov: >> On 05/29/2014 01:21 PM, Richard Weinberger wrote: >>> Am 29.05.2014 11:07, schrieb Pavel Emelyanov: >>>> On 05/29/2014 09:59 AM, Vasily Kulikov wrote: >>>>> On Wed, May 28, 2014 at 23:27 +0400, Pavel Emelyanov wrote: >>>>>> On 05/28/2014 10:28 PM, Vasily Kulikov wrote: >>>>>>> On Wed, May 28, 2014 at 16:44 +0400, Pavel Emelyanov wrote: >>>>>>> It will be simplier >>>>>>> to parse the file -- if 'ns_ids' file contains some ID then this ID for >>>>>>> every ns can be obtained regardless of the specific ID name (SID, PID, >>>>>>> PGID, etc.). >>>>>> >>>>>> True, but given a task PID how to determine which pid namespaces it lives in >>>>>> to get the idea of how PIDs map to each other? Maybe we need some explicit >>>>>> API for converting (ID, NS1, NS2) into (ID)? >>>>> >>>>> AFAIU the idea of the patch is to add a new debugging information which >>>>> can be trivially obtained via 'cat /proc/...': >>>> >>>> I agree, but this ability will be very useful by checkpoint-restore project >>>> too and I'd really appreciate if the API we have for that would be scalable >>>> enough. Per-task proc file works for me, but how about sid-s and pgid-s? >>> >>> What kind of information does CRIU need? >> >> We need to know what pid namespaces a task lives in and how pid, sid and >> pgid look in all of them. A short example with pids only > > So use case is to checkpoint/restore nested containers? :) Yes, but there's one more scenario. AFAIK some applications create pid namespaces themselves, without starting what is typically called "a container" :) And when such an applications are run inside, well ... "more real" container (e.g. using openvz, lxc or docker tools) we face this issue. Thanks, Pavel _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
