A solution for watching your Docker® containers running via Docker Compose for image updates and automatically restarting the compositions whenever an image is refreshed.
Compose Updater is an application which continuously monitors your running docker containers. When a base image is changed, the updated version gets pulled (or built via --pull) from the registry and the docker compose composition gets restarted (via down and up -d).
You'll need to add two labels to the services you want to watch:
version: '3'
services:
web:
image: nginx:alpine
labels:
- "docker-compose-watcher.watch=1"
- "docker-compose-watcher.dir=/home/docker/dir"
docker-compose-watcher.watch=1 exposes the service to Compose Updater.
docker-compose-watcher.dir specifies the path to the directory where this docker-compose.yml lives. If the file is not named docker-compose.yml, you can instead use the label docker-compose-watcher.file to specify the correct path and file name. This is necessary because it's not possible to find the docker-compose.yml from a running container.
Run Docker Compose Watcher using compose:
version: '3'
services:
watcher:
image: virtualzone/compose-updater
restart: always
volumes:
- "/var/run/docker.sock:/var/run/docker.sock:ro"
- "/home/docker:/home/docker:ro"
environment:
INTERVAL: 60
It's important to mount /var/run/docker.sock and the directory your compose files reside in (/home/docker in the example above).
If the registry you're pulling from require authentification, you could mount ~/.docker/config.json from the host inside the watcher service.
Assuming your host user is called ubuntu, adding this line to the volumes declaration of the watcher service should work :
volumes:
# Mount repository configuration (including http(s) settings and credentials) from the host to the container (assuming the host user is called ubuntu)
- "/home/ubuntu/.docker/config.json:/root/.docker/config.json:ro"Note: You'll only need one Compose Updater instance for all your compose services (not one per docker-compose.yml).
Configure Compose Updater via environment variables (recommended) or command line arguments:
| Env | Param | Default | Meaning |
|---|---|---|---|
| INTERVAL | -interval | 60 | Minutes between checks |
| CLEANUP | -cleanup | 0 | Run docker system prune -a -f after each run |
| ONCE | -once | 0 | Run once and exit |
| PRINT_SETTINGS | -printSettings | 1 | Print settings on start |
| UPDATE_LOG | -updateLog | '' | Log file for updates and restarts |
| COMPLETE_STOP | -completeStop | 0 | Restart all services in docker-compose.yml (even unmanaged) after a new image is pulled |
GNU General Public License v3.0
Docker® is a trademark of Docker, Inc.
This project is not affiliated with Docker, Inc.