How to change docker root data directory

The standard data directory used by docker is /var/lib/docker, and since this directory will store all your images, volumes, etc. it can become quite large in a relative small amount of time.

If you want to move the docker data directory on another location you can follow the following simple steps.

1. Stop the docker daemon

sudo service docker stop

2. Add a configuration file to tell the docker daemon what is the location of the data directory

Create docker daemon configuration /etc/docker/daemon.json with following content:

Version before v17.05.0

{ 
   "graph": "/path/to/your/new/docker/root" 
}

“"/path/to/your/new/docker/root”” is the new location you want to use for your new docker data directory.

v17.05.0 and newer

From v17.05.0, the -g or --graph flag for the dockerd or docker daemon command was used to indicate the directory in which to store persistent data and resource configuration and has been replaced with the more descriptive --data-root flag. We create daemon configuration file:

{ 
   "data-root": "/path/to/your/new/docker/root"
}

These flags “graph” were added before Docker 1.0, so will not be removed, only hidden. You still use this flag but simply discourage from using it.

3. Copy the current data directory to the new one

We can use both rsync and cp command:

sudo rsync -aP /var/lib/docker/ "/path/to/your/new/docker/root"
sudo cp -rp /var/lib/docker/* "/path/to/your/new/docker/root/"

4. Rename the old docker directory

Rename old directory to ensure that docker daemon can’t use old directory.

sudo mv /var/lib/docker /var/lib/docker.old

5. Restart the docker daemon

sudo service docker start

6. Test

If everything is ok you should see no differences in using your docker containers.

7. Clean old data.

Alter all, we should clean old data:

rm -rf /var/lib/docker.old