How to Change Docker Root Data Directory

Docker stores all your images, volumes, and containers under /var/lib/docker by default. That directory can balloon quickly, and if your root filesystem is small, you will run out of space before you know it. Moving the data directory to a larger volume is a straightforward fix, and this guide walks you through the stop, configure, migrate, and verify steps for both legacy and modern Docker versions.

1. Stop the Docker daemon

sudo service docker stop

2. Add a configuration file to tell the Docker daemon the new data directory location

Create or edit /etc/docker/daemon.json with the appropriate content for your Docker version.

Version before v17.05.0

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

Replace /path/to/your/new/docker/root with the actual path where you want the new Docker data directory to live.

v17.05.0 and newer

Starting with v17.05.0, the --graph flag was replaced by the more descriptive --data-root flag. Use the following configuration:

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

3. Copy the current data directory to the new location

You can use either rsync or cp:

sudo rsync -aP /var/lib/docker/ /path/to/your/new/docker/root/

or

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

4. Rename the old Docker directory

Renaming (rather than deleting) the old directory gives you a safety net in case something goes wrong.

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

5. Restart the Docker daemon

sudo service docker start

6. Test

Run a quick sanity check. Your existing containers and images should behave exactly as before:

docker ps -a
docker images

If everything looks correct, you are good to proceed.

7. Clean up old data

Once you are confident the new location is working, remove the old directory to reclaim disk space:

sudo rm -rf /var/lib/docker.old

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