Watchtower Install - Removed

UPDATE: 08112025

REMOVED WATCHTOWER FROM VMS CONTAINING DOCKER APPS ON VMS. Watchtower missed many updates and doing it manually for each VM/docker app only took ten minutes.

UPDATE: 04192025

The containrrr/watchtower version of watchtower is no longer actively maintained. There are currently several forks being maintained so I went with the nickfedor/watchtower version from github. At the end of this post are the steps I followed to change each instance of watchtower running in the home lab now. Six VMs on two hypervisors running 22 containers and one watchtower instance on lpt-hp running 14 containers.

Watchtower Installation & Configuration Guide

What This Does

This setup ensures: Automatic updates for all running Docker containers.
Ntfy.sh notifications whenever a container is updated.
Customizable update check interval (default: every 24 hours).

---

Step 1: Install Watchtower

1️⃣ SSH into the VM where Watchtower will run

-bash-

ssh vm-user@vm-ip (e.g. ssh mark@192.168.1.108)

2️⃣ Pull the latest Watchtower image

-bash-

docker pull containrrr/watchtower

3️⃣ Run Watchtower with notifications & a custom interval

-bash-

docker run -d \
--name watchtower \
--restart unless-stopped \
-v /var/run/docker.sock:/var/run/docker.sock \
-e WATCHTOWER_NOTIFICATIONS=shoutrrr \
-e WATCHTOWER_NOTIFICATION_URL="ntfy://ntfy.sh/watchtower-updates" \
containrrr/watchtower --interval 43200

What this does:

• -d → Runs in detached mode (background).
• --restart unless-stopped → Ensures Watchtower restarts if the VM reboots.
• -v /var/run/docker.sock:/var/run/docker.sock → Allows Watchtower to monitor containers.
• -e WATCHTOWER_NOTIFICATIONS=shoutrrr → Enables notifications via ntfy.sh.
• -e WATCHTOWER_NOTIFICATION_URL="ntfy://ntfy.sh/watchtower-updates" → Sends alerts to ntfy.sh.
• --interval 43200 → Check every 12 hours (adjust as needed).

---

Step 2: Verify That Watchtower is Running

Check if Watchtower is running and monitoring containers:

-bash-

docker logs watchtower | grep "Scheduling first run"

If everything is correct, you should see something like:

-bash-

time="2025-02-22T23:02:32Z" level=info msg="Scheduling first run: 2025-02-23 11:02:32 +0000 UTC"
time="2025-02-22T23:02:32Z" level=info msg="Next check in 11 hours, 59 minutes, 59 seconds"

---

Step 3: Test Ntfy.sh Notifications

To make sure notifications work, force an update check:

-bash-

docker exec watchtower /watchtower --run-once

Then, open https://ntfy.sh/watchtower-updates in a browser (or check your ntfy mobile app) to confirm you received an update notification.

---

Step 4: Customize Watchtower (Optional)

** Adjust Update Check Interval**

Change the --interval value when starting Watchtower:

• Every 6 hours: --interval 21600
• Every 24 hours: --interval 86400
• Every 3 days: --interval 259200

To change the interval, stop and remove Watchtower:

-bash-

docker stop watchtower
docker rm watchtower

Then re-run the docker run command with the new interval.

---

Update Only Specific Containers

By default, Watchtower updates all containers. To limit updates to specific containers, add container names at the end of the command:

-bash-

docker run -d \
--name watchtower \
--restart unless-stopped \
-v /var/run/docker.sock:/var/run/docker.sock \
-e WATCHTOWER_NOTIFICATIONS=shoutrrr \
-e WATCHTOWER_NOTIFICATION_URL="ntfy://ntfy.sh/watchtower-updates" \
containrrr/watchtower mealie portainer

This will only update mealie and portainer, leaving other containers untouched.

---

Step 5: Final Checklist

Before calling it done, make sure:
Watchtower is running → docker ps | grep watchtower
Notifications work → Check https://ntfy.sh/watchtower-updates
Update interval is correct → docker logs watchtower | grep "Scheduling first run"

---

TL;DR - Quick Commands

-bash-

ssh vm-user@vm-ip
docker pull containrrr/watchtower
docker run -d \
--name watchtower \
--restart unless-stopped \
-v /var/run/docker.sock:/var/run/docker.sock \
-e WATCHTOWER_NOTIFICATIONS=shoutrrr \
-e WATCHTOWER_NOTIFICATION_URL="ntfy://ntfy.sh/watchtower-updates" \
containrrr/watchtower --interval 43200
docker logs watchtower | grep "Scheduling first run"
docker exec watchtower /watchtower --run-once # Test notifications

---

UPDATE: 04192025

How to change watchtower version to nickfedor/watchtower

docker ps --format "table {{.Names}}\t{{.Image}}"

This will get the actual name of the watchtower container running. Mine were being given random names as watchtower was trying to update them and failing and then giving them a random string name. If needed run the following command.

docker rename [container-name-from-prior-command] watchtower

Then run:

docker stop watchtower && docker rm watchtower

Now reinstall and restart the Watchtower container

docker run -d \
  --name watchtower \
  --restart unless-stopped \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e WATCHTOWER_NOTIFICATIONS=shoutrrr \
  -e WATCHTOWER_NOTIFICATION_URL="ntfy://ntfy.sh/watchtower-updates" \
  -e WATCHTOWER_NOTIFICATION_REPORT=true \
  nickfedor/watchtower \
  --interval 172800 \
  --cleanup \
  --include-restarting \
  --label-enable\

NOTE: This command turns off Watchtower trying to update itself. I will update that manually if needed - but that will be infrequently going forward.

Wait a minute or so and then run the following to confirm it is running and healthy:

docker ps