Watchtower – Automated Updates in Container Manager on a Synology NAS

Last updated on 20 March 2025

What is Watchtower?

Watchtower monitors and automatically updates your containers to the latest versions for you, it is useful as it is not limited to which Docker repositories it can pull from. The Container Manager UI can only notify you of updates for container images from Docker Hub, not the popular GitHub.

Useful external links for this guide

• Watchtower GitHub
• Watchtower Documentation

Let’s Begin

We will be setting up Watchtower using the Project functionality in Container Manager. This uses a compose file to tell Docker how to set up the container and also define some preferences.

Folder Setup

Let’s start by getting a folder set up for the container to use. Open up File Station create the following.

/docker/projects/watchtower-compose

Container Manager

Next we are going to set up a ‘Project’ in Container Manager. Open up Container Manager and click on Project then on the right-hand side click ‘Create’.

In the next screen we will set up our General Settings, enter the following:

We have a couple of different composes available below, the first one is configured to update all running containers at 2am daily.

services:
  watchtower:
    image: containrrr/watchtower:latest
    container_name: watchtower
    environment:
      - TZ=YOURTIMEZONE
      - WATCHTOWER_CLEANUP=true
      - WATCHTOWER_INCLUDE_STOPPED=true
      - WATCHTOWER_REVIVE_STOPPED=false
      - WATCHTOWER_SCHEDULE=0 0 2 * * *
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    restart: unless-stopped

As an addition to the method above you can exclude specific containers from updates by adding this line to their yaml (compose) details. This is likely faster than using method 2

    labels:
      - com.centurylinklabs.watchtower.enable=false

The second has an added section where you can specify the names of the containers you would like to update (use the exact name of the container as per the Synology UI)

services:
  watchtower:
    image: containrrr/watchtower:latest
    container_name: watchtower
    environment:
      - TZ=YOURTIMEZONE
      - WATCHTOWER_CLEANUP=true
      - WATCHTOWER_INCLUDE_STOPPED=true
      - WATCHTOWER_REVIVE_STOPPED=false
      - WATCHTOWER_SCHEDULE=0 0 2 * * *
    command: # add or remove the below as required
      - overseerr
      - plex
      - prowlarr
      - radarr
      - sonarr
      - tautulli
      - watchtower
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    restart: unless-stopped

You can copy and paste the one you wish to use into the blank section in Container Manager.

Environment Variables

We need to make some changes in order for watchtower to know what time it is where you are and what we want it to do. You can amend these in the compose based on your preferences.

Click ‘Next’

You do not need to enable anything on the ‘Web portal settings’ screen click ‘Next’ again

On the final screen click Done which will begin the download of the container images and once downloaded they will be launched!

The image will now be downloaded and extracted. You should see ‘Code 0’ when it has finished.

You will now see your watchtower project running it should have a green status on the left-hand side.

You can now just leave Watchtower running you will never need to manually update your containers again.

FAQ

I keep getting X container has stopped unexpectedly errors!
DSM does not know or understand that Watchtower is issuing commands in the background. So it makes the assumption that a container was stopped unexpectedly, but we know it was Watchtower doing an update.

Do I need to update Watchtower itself?
Nope it updates itself – quite clever really.

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