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Docker Data Directory Migration Script

This Bash script moves the Docker data directory from the default location (/var/lib/docker) to a new directory (e.g. /home/docker), ensuring that Docker is reconfigured and restarted correctly.

Download script here

The script must be run by the root or sudo user.

📁 Script Purpose

  • Stop Docker safely
  • Copy Docker data to a new directory using rsync
  • Update Docker daemon config (daemon.json)
  • Start Docker with the new data root
  • Verify and remove the old directory if successful

✅ Requirements

  • OS: Debian/Ubuntu
  • Docker installed
  • Sudo privileges
  • rsync (installed by the script if missing)

⚙️ Configuration Variables

Variable Default Value Description
NEW_DOCKER_DIR /home/docker New location for Docker data
OLD_DOCKER_DIR /var/lib/docker Default Docker data location
DOCKER_CONFIG /etc/docker/daemon.json Docker configuration file
DOCKER_CONFIG_BAK Timestamped backup of the config Stored in the same folder

Step-by-Step Behavior

1. Install rsync (if missing)

if ! command -v rsync >/dev/null 2>&1; then
  sudo apt update
  sudo apt install -y rsync
fi

2. Create Target Directory

sudo mkdir -p /home/docker

3. Stop Docker

Stops both docker.socket and docker service:

sudo systemctl stop docker.socket || true
sudo systemctl stop docker

4. Copy Docker Data

All files from the old Docker directory are copied with permissions preserved:

sudo rsync -aP /var/lib/docker/ /home/docker/

5. Backup and Update daemon.json

Creates a backup if the config file exists and rewrites it to use the new data root:

sudo cp /etc/docker/daemon.json /etc/docker/daemon.json.bak.YYYYMMDDHHMMSS
echo '{ "data-root": "/home/docker" }' | sudo tee /etc/docker/daemon.json

6. Restart Docker

sudo systemctl start docker

7. Verify Configuration

Checks if Docker is using the new root path:

docker info | grep -q "Docker Root Dir: /home/docker"

If verified:

  • Deletes the old directory
  • Prints success message

Otherwise:

  • Prints error
  • Advises to restore from the backup

🔁 Restore Instructions (if needed)

If Docker doesn't start correctly or the new path doesn't apply:

sudo cp "$DOCKER_CONFIG_BAK" "$DOCKER_CONFIG"
sudo systemctl restart docker

🛉 Cleanup

Only if verification is successful:

sudo rm -rf /var/lib/docker

💡 Notes

  • The script uses set -e to exit on error — it will stop on any failed command unless explicitly ignored (e.g., || true).
  • It is safe to re-run — idempotent for most actions.
  • All actions are logged to the terminal for easy tracking.

📌 Example Usage

Run the script with bash or chmod +x and execute directly:

chmod +x migrate-docker-root.sh
./migrate-docker-root.sh

Changelog

Date Author Message
2026-02-25 aresnikowa Merge remote-tracking branch 'origin/master'