Docker: Move Docker data directory to new location

The standard data directory used for docker is /var/lib/docker, and since this directory will store all your images, volumes, etc. it can become quite large.

Follow the steps below to move the Docker data directory to a new location. This makes especially sense if you want to avoid running out of disk space on your root partition.

Stop the Docker daemon.

sudo service docker stop

Edit the config file:

sudo vi /etc/docker/daemon.json

And set the data root:

{ 
   "data-root": "/mnt/sdb/docker"
}

Move the current docker directory to the new directory.

sudo mv /var/lib/docker /mnt/sdb/docker

Restart the Docker deamon.

sudo service docker start

Test if all services work as expected.

docker ps -a
docker info -f '{{ .DockerRootDir}}'