[CRIU] [P.haul + Docker] Missing Running States During Live Migration of Container

[Pavel Emelyanov]

On 02/20/2017 10:23 PM, Lele Ma wrote:
> 
> On Mon, Feb 20, 2017 at 1:16 PM, Pavel Emelyanov <xemul at virtuozzo.com <mailto:xemul at virtuozzo.com>> wrote:
> 
>     On 02/19/2017 10:50 PM, Lele Ma wrote:
>     > Hi All,
>     >
>     > I am testing container live migration with this github repos <https://github.com/boucher/docker/tree/v1.10_2-16-16-experimental <https://github.com/boucher/docker/tree/v1.10_2-16-16-experimental>> for docker-1.10-dev. I found the container not restored exactly where it's checkpointed. For example:
>     >
>     > The container I run
>     >      docker run  -d busybox  /bin/sh -c 'echo > /foo; max=1000000; i=0; while [ $i -lt $max ] ; do date >> /foo; date +%s >> /foo; echo "i=$i" >> /foo; i=$(expr $i + 1 ); sleep 0.0001; done'
>     >
>     > After migrated using p.haul, I got the /foo in target node:
>     > .....
>     > Sun Feb 19 03:23:13 UTC 2017
>     > 1487474593
>     > i=4247
>     > Sun Feb 19 03:23:13 UTC 2017
>     > 1487474593
>     > i=4248                       -----> before migration
>     > i=7545                       -----> after migartion ( it is supposed to be i=4249 )
>     > Sun Feb 19 03:23:20 UTC 2017
>     > 1487474600
>     > i=7546
>     > Sun Feb 19 03:23:20 UTC 2017
>     > 1487474600
>     > i=7547
>     > ......
>     > The printed numbers jump from 'i=4248' to 'i=7545' instead of increasing by one. It seems that it ignores
>     > some computation status of the docker containers. But I am not sure where it goes wrong. However, when I
>     > checkpoint and restore the container locally, the number increase continuously with no such jumping.
> 
>     Where do you get these numbers from? Docker console or some file on disk?
> 
> 
> It's from the file '/foo' inside container. ( The container is running /bin/sh -c 'echo > /foo; 
> max=1000000; i=0; while [ $i -lt $max ] ; do date >> /foo; date +%s >> /foo; echo "i=$i" >> /foo; 
> i=$(expr $i + 1 ); sleep 0.0001; done' )

Then this is likely a race between images sync and filesystem sync.
You can check your /foo file on the source node right after container
migration, it should contain the missing numbers :)

What p.haul do you use, btw?

>     > Does anyone know where goes wrong and how should it be fixed?  Thank you in advance!
>     >
>     > Best,
>     > Lele
>     >
>     >
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>