Migrate from containrrr/watchtower to nickfedor Fork (2026) — Step-by-Step

What Changes, What Doesn't

Item	Change Required?
Image name	✓ Change to nickfedor/watchtower
All WATCHTOWER_* environment variables	✓ No change — 100% identical
Docker labels on monitored containers	✓ No change — all labels work identically
Volume mounts (/var/run/docker.sock)	✓ No change
Port mappings (HTTP API)	✓ No change
Shoutrrr notification URLs	✓ No change
Docker Swarm global service config	✓ No change beyond image name

Method 1 — Docker Compose (Most Common)

This covers the typical setup where Watchtower is defined in a docker-compose.yml file.

Step 1: Open your docker-compose.yml and change the image line:

# Before — archived image
services:
  watchtower:
    image: containrrr/watchtower
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      WATCHTOWER_CLEANUP: "true"
      WATCHTOWER_SCHEDULE: "0 0 4 * * *"
    restart: unless-stopped

# After — active fork (only the image line changes)
services:
  watchtower:
    image: nickfedor/watchtower
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      WATCHTOWER_CLEANUP: "true"
      WATCHTOWER_SCHEDULE: "0 0 4 * * *"
    restart: unless-stopped

Step 2: Pull the new image and restart the container:

docker compose pull watchtower
docker compose up -d watchtower

Step 3: Verify the new container is running:

docker compose logs watchtower

You should see startup logs from the nickfedor fork. The version string will differ from the containrrr v1.7.1 if the fork has issued newer releases.

Method 2 — docker run

If you run Watchtower with a plain docker run command, update the image name and recreate the container:

# Step 1: Stop and remove the existing containrrr container
docker stop watchtower
docker rm watchtower

# Step 2: Pull the nickfedor fork
docker pull nickfedor/watchtower

# Step 3: Start with the new image (all flags remain the same)
docker run -d \
  --name watchtower \
  --restart unless-stopped \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_CLEANUP=true \
  -e WATCHTOWER_SCHEDULE="0 0 4 * * *" \
  nickfedor/watchtower

Replace the environment variables and flags with your existing configuration — only the image name at the end changes.

Method 3 — Docker Swarm

If Watchtower runs as a global service in a Docker Swarm cluster:

# Update the service image — Swarm handles rolling restart automatically
docker service update \
  --image nickfedor/watchtower \
  watchtower

Or, if you use a Swarm stack file, update the image: line and redeploy:

docker stack deploy -c watchtower-stack.yml watchtower

Method 4 — Portainer Stack

1. In the Portainer UI, navigate to Stacks and select your Watchtower stack.
2. Click Editor and change image: containrrr/watchtower to image: nickfedor/watchtower.
3. Click Update the stack.
4. Portainer will pull the new image and restart the Watchtower container automatically.

Verifying the Migration

After the migration, confirm Watchtower is running correctly:

# Check the running container
docker ps | grep watchtower

# Check logs for startup confirmation
docker logs watchtower --tail 20

# Trigger a manual run-once check (optional)
docker run --rm \
  -v /var/run/docker.sock:/var/run/docker.sock \
  nickfedor/watchtower --run-once --debug

Look for Checked X container(s) in the run-once output — this confirms the fork is reading your running containers correctly.

Common Migration Issues

Issue: Old containrrr image is still running after compose up
Make sure you ran docker compose pull watchtower before docker compose up -d. If the local cache still has the containrrr image, Docker Compose may not pull the new one automatically without the explicit pull step.

Issue: "no such image" error after changing image name
Run docker pull nickfedor/watchtower explicitly, then retry. Check that your internet connection can reach Docker Hub.

Issue: Container keeps restarting after migration
Check docker logs watchtower for the error. Common causes after a fork switch are missing Docker socket (check the volume mount) or an environment variable typo introduced during the edit. Compare your configuration against the working examples above.