Updating with Watchtower

Watchtower polls a registry and restarts running containers when a newer image is published. It is the simplest “just keep me current” option — and the trade-off is that updates happen without review.

Basic Setup

services:
  watchtower:
    image: containrrr/watchtower
    container_name: watchtower
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      WATCHTOWER_CLEANUP: "true"
      WATCHTOWER_POLL_INTERVAL: "3600"
    restart: unless-stopped

Opting Containers In or Out

By default Watchtower watches every running container. To limit it, set:

environment:
  WATCHTOWER_LABEL_ENABLE: "true"

…and label the containers you want updated:

services:
  my-app:
    image: ghcr.io/trueforge-org/my-app:latest
    labels:
      - com.centurylinklabs.watchtower.enable=true

Tag Selection Matters

Watchtower updates the tag you deployed. Pair it with our tag formats so you only receive the level of change you want:

Tag	Result
`rolling`	Every rebuild
`Major`	Patch + minor + digest updates
`Major.Minor`	Patch + digest updates
`Major.Minor.Patch`	Digest updates only