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Watchtower – Automated Updates in Container Manager on a Synology NAS

Last updated on 28 January 2024

Important or Recent Updates
Historic UpdatesDate
New guide update for DSM7.2 and Container Manager30/04/2023
Added labels to GlueTUN container guide so updated information in this one to coincide06/05/2023
Added a 3rd option to just exclude specific containers via a label.23/11/2023
Historic Updates


What is Watchtower?

Watchtower requires access to the Docker socket, we are unable to set this up via the Synology GUI. This means we will be using Docker-Compose.

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.

Folders
/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:

SectionSetting
Project Name:watchtower
Path:/docker/projects/watchtower-compose
Source:Create docker-compose.yml

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

YAML
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

YAML
    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)

YAML
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.

VariableValueWhat it does
TZEurope/LondonChange this to your own timezone
WATCHTOWER_CLEANUPtrue or falseWe want to clean up the old docker images, if you don’t turn this on over the course of a few months you will find that the images start to eat a lot of space, and they are not even being used. (true or false)
WATCHTOWER_INCLUDE_STOPPEDtrue or falseDo you want to update any stopped containers, the container will stay stopped after being updated (true or false)
WATCHTOWER_REVIVE_STOPPEDtrue or falseIf a stopped container is updated do you want Watchtower to start it up? (true or false)
WATCHTOWER_SCHEDULE0 0 2 * * *Rather than setting the number of seconds to wait between checks you can set a schedule. The default I use for the guide is 2am every day, you can work out your own schedule using a cron schedule generator.

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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Published inDockerSynologyUpdating Containers 7.2

24 Comments

  1. Shiba Shiba

    Hi Doc, love your guides. Thanks so much for the effort you put in.

    When I put “0 0 2 * * *” into that handy crontab generator link, it says: “At 12:00 AM, on day 3 of the month”

    For a 2am schedule, should it not be: “0 2 * * *”

  2. Patrick Heywood Patrick Heywood

    I see watchtower (I am re-installing everything here) does not use the synobridge network, and the installation creates a watch_tower default network in container manager (DSM 7.2). Is this expected behavior, or do I include a synobridge network_mode statement in the compose file?

    • Dr_Frankenstein Dr_Frankenstein

      Hey,it doesn’t need access to the synobridge network so it is not added. It can sit on its own.

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