[CRIU] question on live migration for docker container using CRIU

[Saied Kazemi]

Hi Mona,

As Pavel pointed out, the error is due to not being able to bind mount
an external file.  But this is not because a the --ext-mount-map
command line option is missing.  It's because docker_cr.sh does not
know the dockerinit file name in /var/lib/docker/init (by default, it
assume Docker 1.0.0).

Since you are running Docker 1.4, you need to change the following
BIND_MOUNT line in docker_cr.sh to reflect what you have in
/var/lib/docker/init:

# since older versions of docker bind mount /.dockerinit but
# the path cannot be queried by docker inspect, we have to
# hard code it here
BIND_MOUNT[/.dockerinit]="${DOCKER_HOME}/init/dockerinit-1.0.0"

Hope this helps.

--Saied


On Wed, Dec 31, 2014 at 2:28 AM, Pavel Emelyanov <xemul at parallels.com> wrote:
> On 12/31/2014 04:36 AM, mona kashkoush wrote:
>>
>> i tried to  do a live migration for docker container using CRIU 1.4 but dumping failed and this error appeared
>>
>> $  criu dump --tree <pid> --images-dir <path-to-existing-directory> --leave-stopped
>>
>> Error (mount.c:624): 125:./etc/hosts doesn't have a proper root mount
>> Error (files-reg.c:764): Unaccessible path opened 52:21244, need 5:1029
>> Error (cr-dump.c:1601): Dump files (pid: 3906) failed with -1
>> Error (cr-dump.c:1964): Dumping FAILED.
>>
>> and when i used the automated script "docker_cr.sh " for docker container migration , this succeeded for
>> dumping  but failed for restoring and this error appeared
>>
>> $ /src/criu-1.4/contrib/docker_cr.sh -r -v <container_id>
>>
>> restore failed
>> (00.072030)      1: Error (mount.c:1543): Can't mount at ./.dockerinit: No such file or directory
>
> Hm... This looks like some missed --ext-mount-map thing. Can you find out the
> exact command line docker_cr.sh calls CRIU with?
>
> Hopefully Saied (in Cc) can also advise something.
>
>> (00.072076) Error (cr-restore.c:1838): Restoring FAILED.
>>
>> * this is information about docker which i used
>>
>> Storage Driver: aufs
>>  Root Dir: /var/lib/docker/aufs
>>  Dirs: 67
>> Execution Driver: native-0.2
>> Kernel Version: 3.13.0-43-generic
>>
>> thanks for your time
>>
>> --
>> Mona Salah
>> Research Assistant
>> IRI institute
>> The City of Scientific Research and Technology Applications,Alex , Egypt
>>
>>
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>