watchtower

Watchtower is an application that will monitor your running Docker containers and watch for changes to the images that those containers were originally started from. If watchtower detects that an image has changed, it will automatically restart the container using the new image.

docker-compose.yml

watchtower:
  image: centurylink/watchtower
  command: >
    mysql
    mongo
    nginx
    redis
  volumes:
    - /var/run/docker.sock:/var/run/docker.sock
  restart: always

It'll monitor all containers if no command in YAML.

Up and Running

$ docker-compose up -d

$ docker-compose logs
watchtower_1 | time="2015-09-02T02:31:39Z" level=info msg="Checking containers for updated images"
watchtower_1 | time="2015-09-02T02:31:56Z" level=info msg="Found new redis:latest image (3d86...76)"
watchtower_1 | time="2015-09-02T02:31:56Z" level=info msg="Stopping /redis (8f51...f4) with SIGTERM"
watchtower_1 | time="2015-09-02T02:32:06Z" level=info msg="Starting /redis"
watchtower_1 | time="2015-09-02T02:37:06Z" level=info msg="Checking containers for updated images"
watchtower_1 | time="2015-09-02T02:42:10Z" level=info msg="Checking containers for updated images"