[CRIU] [Users] socket will take at least 0.5 seconds to recovery after docker restore done

[Yanbao Cui]

Hi Pavel,

my test env and test results are as follows

ENV:

tcp client on host: 192.168.9.170

tcp server in docker: 192.168.9.129

udp client in docker: 192.168.9.129

udp server on host: 192.168.9.170



migrate docker container from host 192.168.9.170 to host 192.168.9.180



Summarize:

migration time: checkpoint+restore = 0.569+1.709 = 2.278s

existing socket hang time: 3.6s, actually is 3.6-2.278 = *1.322s*, except
migration downtime



In tcpdump file timestamp is 3.941260 - 7.619094 for tcp, timestamp
4.012874 - 7.619208 for udp



---

root at 192.168.9.170:~# time ./dockercrnfs.sh 192.168.9.180 00dd5314605f

start checkpoint: 2015-07-23 00:44:26.057426748

00dd5314605f1952a727d662860ca38b9d4c4a46761f74d445a8a4a2d8343ee2



real    0m0.569s

user    0m0.011s

sys     0m0.000s



end checkpoint: 2015-07-23 00:44:26.637416792



start restore on host 192.168.9.180: 2015-07-23 00:44:27.893451353

00dd5314605f1952a727d662860ca38b9d4c4a46761f74d445a8a4a2d8343ee2



real    0m1.709s

user    0m0.011s

sys     0m0.008s



end restore on host 192.168.9.180: 2015-07-23 00:44:29.604002575

---


​​

On Tue, Jul 21, 2015 at 11:54 PM, Pavel Emelyanov <xemul at parallels.com>
wrote:

> On 07/21/2015 06:25 PM, Yanbao Cui wrote:
> > thanks Saied!
> > The delay is happened after restore. The -existing- socket(s) cannot
> work, but at
> > the same time ping the container IP is OK.
> >
> > So I am confused that the delay is caused by Docker or CRIU? Because it
> seems that
> > it only happened in Docker migration with CRIU
>
> I would say that this is related to TCP checkpoint-restore. The restored
> connection
> starts with zero window and sends the probe to remote side to get it's
> actual value.
> This can be the reason for delay.
>
> Can you collect tcpdump for your connection with timestamps starting from
> the moment
> of restore so we could look at what packets are traveling?
>
> -- Pavel
>
>


-- 
Best Regards
Cui Yanbao | 崔言宝
--
龍生玖天，豈能安於凡塵！
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openvz.org/pipermail/criu/attachments/20150723/41de3d78/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: docker migration tcpdump.cap
Type: application/octet-stream
Size: 42125 bytes
Desc: not available
URL: <http://lists.openvz.org/pipermail/criu/attachments/20150723/41de3d78/attachment-0001.obj>