Docker multiple Volume-driver

You're right. Since you can have multiple containers with volumes on their own, you need to keep track which volume corresponds to which container. How to do that depends on your setup: I use the name -data for the data container, so it's obvious to which container a image belongs. That way it can be backed up like this:

VOLUME=`docker inspect $NAME-data | jq '.[0].Volumes["/path/in/container"]'`
tar -C $VOLUME . -czvf $NAME.tar.gz

Now you just need to rebuild your image and recreate your data container:

cat $NAME.tar.gz | docker run -name $NAME-data -v /path/in/container \
                              -i busybox tar -C /path/int/container -xzf -

So this means you need to backup:

• Dockerfile
• volume
• volume path in container
• name of the container the volume belongs to

Update: In the meanwhile I created a tool to backup containers and their volume(s) (container(s)): https://github.com/discordianfish/docker-backup and a backup image that can create backups and push them to s3: https://github.com/discordianfish/docker-lloyd

Take a look at docker export.

To quickly list the files in your container:

docker export CONTAINER|tar -t

To export:

docker export CONTAINER>snapshot.tar
docker export CONTAINER|tar x PATH-IN-CONTAINER

Or to look at a file:

docker export CONTAINER|tar x --to-stdout PATH-IN-CONTAINER
# e.g. 
docker export consul|tar x --to-stdout etc/profile

Docker 1.8 supports cp:

https://docs.docker.com/reference/commandline/cp/

Usage:  docker cp [options] CONTAINER:PATH LOCALPATH|-
        docker cp [options] LOCALPATH|- CONTAINER:PATH

update: you should ssh to your docker machine when you run this.