Docker Image Auto-Update

Docker Compose conveniently manages containers but cannot automatically update images. With so many images, you can’t manually update each one. Fortunately, Watchtower solves this. Recent GitHub commits are from two years ago, showing the code is stable enough to use with confidence.

Installation

Installation is very simple. Here’s the compose file:

services:
  watchtower:
    image: containrrr/watchtower
    container_name: watchtower
    restart: unless-stopped
    environment:
      - TZ=America/Toronto
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    command:
      --interval 86400 --label-enable --cleanup
    labels:
      - "com.centurylinklabs.watchtower.enable=false"

Usage

Usage is very simple. Add these two lines to the compose of any image you want to auto-update. Watchtower accesses docker.sock, scans for images needing updates, and if true is found, automatically downloads the new image and deletes the old one. The interval in the compose’s command is the update check frequency. 86400 means check once daily. Everything is seamless after configuration.

labels:
  - "com.centurylinklabs.watchtower.enable=true"