docker-update

A Bash script that keeps Docker Compose projects up to date by pulling fresh images and restarting only the projects where something actually changed.

What it does

• Scans every subdirectory of /volume2/docker/ for a Compose file
• Skips projects with no running containers
• Pulls the latest images for each running project
• Restarts a project only if at least one image was updated — no unnecessary downtime
• Prints a colour-coded summary of what was updated, skipped, and failed

Requirements

• Bash 4+
• Docker with the Compose plugin (docker compose) or standalone docker-compose
• sudo access for Docker commands

Configuration

The scan root is hardcoded at the top of the script:

COMPOSE_ROOT="/volume2/docker"

Change this to match your setup before running.

Usage

Make the script executable once:

chmod +x docker-update.sh

Run manually:

./docker-update.sh

Cron example

Run every night at 03:00:

0 3 * * * /path/to/docker-update.sh >> /var/log/docker-update.log 2>&1

Colour output is suppressed automatically when running non-interactively.

How it works

1. Detects whether to use docker compose (plugin) or docker-compose (standalone)
2. Loops over each subdirectory in COMPOSE_ROOT
3. Looks for a Compose file (docker-compose.yml, docker-compose.yaml, compose.yml, compose.yaml)
4. Counts running containers — skips the project if none are running
5. Runs compose pull and inspects the output for update markers (Pull complete, Downloaded newer image, Pulled, etc.)
6. If an update is found: runs compose down then compose up -d
7. Prints a summary and exits with code 1 if any project failed

License

MIT