[CRIU] Docker HOWTO

Saied Kazemi saied at google.com
Fri Sep 12 09:47:10 PDT 2014 

I just requested an account so that I'd have edit permission.  As soon as
it's set up, I'll add it to the Docker HOWTO page.

--Saied



On Fri, Sep 12, 2014 at 12:59 AM, Pavel Emelyanov <xemul at parallels.com>
wrote:

> On 09/11/2014 10:11 PM, Saied Kazemi wrote:
> > Great!  Here is some additional text for the HOWTO page that introduces
> > docker_cr.sh and explains its usage.
>
> It's very useful, thanks :) Can you integrate this text into
> the http://criu.org/Docker page?
>
> > --Saied
> >
> >
> > Helper Script
> >
> > As seen in the above examples, the CRIU command line for checkpointing
> and
> > restoring a Docker container is pretty long.  For restore, there is also
> > an additional step to set up the root filesystem before invoking CRIU.
> >
> > To automate the C/R process, there is a helper script in the contrib
> > subdirectory of CRIU sources, called docker_cr.sh.  In addition to
> > invoking CRIU, this helper script sets up the root filesystem for AUFS,
> > UnionFS, and VFS for restore.
> >
> > With docker_cr.sh, all you have to provide is the container ID.
> > If you don't specify a container ID, docker_cr.sh will list all running
> > containers and prompt you to choose one.  Also, as shown in the help
> > output below, by setting the appropriate environment variable, it's
> > possible to tell docker_cr.sh which Docker and CRIU binaries to use,
> > where Docker's home directory is, and where CRIU should save and look
> > for its image files.
> >
> > # docker_cr.sh --help
> > Usage:
> > docker_cr.sh -c|-r [-hv] [<container_id>]
> > -c, --checkpointcheckpoint container
> > -h, --helpprint help message
> > -r, --restorerestore container
> > -v, --verboseenable verbose mode
> >
> > Environment:
> > DOCKER_HOME(default /var/lib/docker)
> > CRIU_IMG_DIR(default /var/lib/docker/criu_img)
> > DOCKER_BINARY(default docker)
> > CRIU_BINARY(default criu)
> >
> > Below is an example to checkpoint and restore Docker container 4397:
> >
> > # docker_cr.sh -c 4397
> > dump successful
> > # docker_cr.sh -r 4397
> > restore successful
> >
> > Optionally, you can specify -v to see the commands that docker_cr.sh
> > executes.  For example:
> >
> > # docker_cr.sh -c -v 40d3
> > docker binary: docker
> > criu binary: criu
> > image directory:
> /var/lib/docker/criu_img/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> > container root directory:
> /var/lib/docker/aufs/mnt/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> >
> > criu dump -v4 -D
> /var/lib/docker/criu_img/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> -o dump.log --manage-cgroups --evasive-devices --ext-mount-map
> /etc/resolv.conf:/etc/resolv.conf --ext-mount-map /etc/hosts:/etc/hosts
> --ext-mount-map /etc/hostname:/etc/hostname --ext-mount-map
> /.dockerinit:/.dockerinit -t 5991 --root
> /var/lib/docker/aufs/mnt/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> >
> > dump successful
> > (00.020827) Dumping finished successfully
> >
> > # docker_cr.sh -r -v 40d3
> > docker binary: docker
> > criu binary: criu
> > image directory:
> /var/lib/docker/criu_img/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> > container root directory:
> /var/lib/docker/aufs/mnt/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> >
> > mount -t aufs -o
> >
> /var/lib/docker/aufs/diff/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> >
> /var/lib/docker/aufs/diff/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf-init
> >
> /var/lib/docker/aufs/diff/a9eb172552348a9a49180694790b33a1097f546456d041b6e82e4d7716ddb721
> >
> /var/lib/docker/aufs/diff/120e218dd395ec314e7b6249f39d2853911b3d6def6ea164ae05722649f34b16
> >
> /var/lib/docker/aufs/diff/42eed7f1bf2ac3f1610c5e616d2ab1ee9c7290234240388d6297bc0f32c34229
> >
> /var/lib/docker/aufs/diff/511136ea3c5a64f264b78b5433614aec563103b4d4702f3ba7d4d2698e22c158
> > none
> >
> /var/lib/docker/aufs/mnt/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> >
> > criu restore -v4 -D
> /var/lib/docker/criu_img/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> -o restore.log --manage-cgroups --evasive-devices --ext-mount-map
> /etc/resolv.conf:/var/lib/docker/containers/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf/resolv.conf
> --ext-mount-map
> /etc/hosts:/var/lib/docker/containers/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf/hosts
> --ext-mount-map
> /etc/hostname:/var/lib/docker/containers/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf/hostname
> --ext-mount-map /.dockerinit:/var/lib/docker/init/dockerinit-1.0.0 -d
> --root
> /var/lib/docker/aufs/mnt/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf
> --pidfile
> /var/lib/docker/criu_img/40d363f564e00a2f893579fa012a200e475dcf8df47f2a22b7dd0860ffc3d7bf/restore.pid
> >
> > restore successful
> > (00.408807) Restore finished successfully. Resuming tasks.
> >
> > root      6206     1  1 10:49 ?        00:00:00 /bin/sh -c i=0; while
> true; do echo $i >> /foo; i=$(expr $i + 1); sleep 3; done
> >
> >
> >
> > On Tue, Sep 9, 2014 at 5:10 AM, Pavel Emelyanov <xemul at parallels.com
> <mailto:xemul at parallels.com>> wrote:
> >
> >     On 09/03/2014 11:28 PM, Filipe Brandenburger wrote:
> >     > Acked-by: Filipe Brandenburger <filbranden at google.com <mailto:
> filbranden at google.com>>
> >     >
> >     > On Wed, Sep 3, 2014 at 12:27 PM, Saied Kazemi <saied at google.com
> <mailto:saied at google.com>> wrote:
> >     >> As promised, here is a shell script to simplify checkpointing and
> restoring
> >     >> a Docker container.  The usage is pretty simple and obvious.  Try
> >     >> docker_cr.sh --help to get started.  I suggest adding this file
> to the
> >     >> scripts subdirectory of CRIU and installing it where criu is
> installed, but
> >     >> I have not modified the Makefile.
> >     >>
> >     >> I'd like to acknowledge Filipe's time for his review and feedback.
> >     >>
> >     >> Cheers!
> >
> >     Sorry for the delay. The patch is applied with the scripts/ ->
> contrib/
> >     directory change. Huge thanks!
> >
> >
> >
> >
> > _______________________________________________
> > CRIU mailing list
> > CRIU at openvz.org
> > https://lists.openvz.org/mailman/listinfo/criu
> >
>
>
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