How to change Docker data directory

Problem

By default, Docker stores the data of its images, containers and volumes in the /var/lib/docker directory. Sometimes, you may want to request Docker to store its data in a different directory or partition.

For example, on my computers I keep separate partitions for root / and home /home and the latter is much bigger than the former. So, I prefer that Docker use a directory in my /home partition to store its data.

Solution

To change the data directory used by Docker:

• Clean up /var/lib/docker by removing all the images currently used by Docker:

$ docker system prune -a

• Create a directory for Docker’s data whereever you want. I created one in my home partition: /home/joe/docker_data.

• Add the following lines to the /etc/docker/daemon.json file:

"data-root": "/home/joe/docker_data",
"storage-driver": "overlay2"

• Restart Docker daemon:

$ sudo systemctl restart docker

When you pull down images, you will now see the new data directory getting populated.