linuxserver/modmanager

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https://github.com/linuxserver/docker-modmanager

Modmanager is a centralised tool for downloading and updating docker mods for all your other Linuxserver containers.

Supported Architectures

We utilise the docker manifest for multi-platform awareness. More information is available from docker https://distribution.github.io/distribution/spec/manifest-v2-2/#manifest-list and our announcement https://blog.linuxserver.io/2019/02/21/the-lsio-pipeline-project/.

Simply pulling lscr.io/linuxserver/modmanager:latest should retrieve the correct image for your arch, but you can also pull specific arch images via tags.

The architectures supported by this image are:

Application Setup

You can specify mods to download via the DOCKER_MODS environment variable like any other container, or allow discovery through docker by mounting the docker socket into the container (or configuring a suitable alternative endpoint via the built-in DOCKER_HOST environment variable). Whichever option you choose the appropriate DOCKER_MODS environment variable must still be present on the containers that need to install them.

The Modmanager container will download all needed mods on startup and then check for updates every 6 hours; if you're using docker discovery it will automatically pick up any new mods.

You can then mount your /modcache path into any other Linuxserver container and they will pull their mods from there rather than downloading them each time.

If a mod requires additional packages to be installed, each container will still need to download them each time it is recreated.

Note that the Modmanager container itself does not support applying mods or custom files/services.

Modmanager is only supported for use with Linuxserver images built after 2025-01-01, while it may work with 3rd party containers using our images as a base we will not provide support for them.

Security ***ations

Mapping docker.sock is a potential security liability because docker has root access on the host and any process that has full access to docker.sock would therefore also have root access on the host. The docker API has no built-in way to set limitations on access, however, you can use a proxy for docker.sock via a solution like https://github.com/linuxserver/docker-socket-proxy, which adds the ability to limit API access to specific endpoints.

Multiple Hosts

[!NOTE] Make sure you fully understand what you're doing before you try and set this up as there are lots of ways it can go wrong if you're just guessing.

Modmanager can query & download mods for remote hosts, as well as the one on which it is installed. At a very basic level if you're just using the DOCKER_MODS env and not docker discovery, simply mount the /modcache folder on your remote host(s), ensuring it is mapped for all participating containers.

If you are using docker discovery, our only supported means for connecting to remote hosts is https://github.com/linuxserver/docker-socket-proxy/. Run an instance on each remote host:

[!WARNING] DO NOT expose a socket proxy to your LAN if it allows any write operations (POST=1, ALLOW_RESTART=1, etc) or exposes any API elements that are not absolutely necessary. NEVER expose a socket proxy to your WAN.

yml
  modmanager-dockerproxy:
    image: lscr.io/linuxserver/socket-proxy:latest
    container_name: modmanager-dockerproxy
    environment:
      - CONTAINERS=1
      - POST=0
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    tmpfs:
      - /run
    ports:
      - 2375:2375
    restart: unless-stopped
    read_only: true

And then add it to the DOCKER_MODS_EXTRA_HOSTS env using the full protocol and port, separating multiple servers with a pipe (|), e.g.

yaml
  - DOCKER_MODS_EXTRA_HOSTS=tcp://host1.example.com:2375|tcp://host2.example.com:2375|tcp://192.168.0.5:2375

As above you will need to mount the /modcache folder on your remote host(s), ensuring it is mapped for all participating containers.

Usage

To help you get started creating a container from this image you can either use docker compose or the docker cli.

[!NOTE] Unless a parameter is flaged as 'optional', it is mandatory and a value must be provided.

docker compose (recommended, https://docs.linuxserver.io/general/docker-compose)

yaml
---
services:
  modmanager:
    image: lscr.io/linuxserver/modmanager:latest
    container_name: modmanager
    environment:
      - DOCKER_MODS= `#optional`
      - DOCKER_HOST= `#optional`
      - DOCKER_MODS_EXTRA_HOSTS= `#optional`
    volumes:
      - /path/to/modcache:/modcache
      - /var/run/docker.sock:/var/run/docker.sock:ro `#optional`
    restart: unless-stopped

docker cli (https://docs.docker.com/engine/reference/commandline/cli/)

bash
docker run -d \
  --name=modmanager \
  -e DOCKER_MODS= `#optional` \
  -e DOCKER_HOST= `#optional` \
  -e DOCKER_MODS_EXTRA_HOSTS= `#optional` \
  -v /path/to/modcache:/modcache \
  -v /var/run/docker.sock:/var/run/docker.sock:ro `#optional` \
  --restart unless-stopped \
  lscr.io/linuxserver/modmanager:latest

Parameters

Containers are configured using parameters passed at runtime (such as those above). These parameters are separated by a colon and indicate <external>:<internal> respectively. For example, -p 8080:80 would expose port 80 from inside the container to be accessible from the host's IP on port 8080 outside the container.

Support Info

• Shell access whilst the container is running:

bash
docker exec -it modmanager /bin/sh

• To monitor the logs of the container in realtime:

bash
docker logs -f modmanager

• Container version number:

bash
docker inspect -f '{{ index .Config.Labels "build_version" }}' modmanager

• Image version number:

bash
docker inspect -f '{{ index .Config.Labels "build_version" }}' lscr.io/linuxserver/modmanager:latest

Updating Info

Most of our images are static, versioned, and require an image update and container recreation to update the app inside. With some exceptions (noted in the relevant readme.md), we do not recommend or support updating apps inside the container. Please consult the Application Setup section above to see if it is recommended for the image.

Below are the instructions for updating containers:

Via Docker Compose

• Update images:

  • All images:

  bash
  docker compose pull
  

  • Single image:

  bash
  docker compose pull modmanager
  

• Update containers:

  • All containers:

  bash
  docker compose up -d
  

  • Single container:

  bash
  docker compose up -d modmanager
  

• You can also remove the old dangling images:

bash
docker image prune

Via Docker Run

• Update the image:

bash
docker pull lscr.io/linuxserver/modmanager:latest

• Stop the running container:

bash
docker stop modmanager

• Delete the container:

bash
docker rm modmanager

• You can also remove the old dangling images:

bash
docker image prune

Image Update Notifications - Diun (Docker Image Update Notifier)

[!TIP] We recommend https://crazymax.dev/diun/ for update notifications. Other tools that automatically update containers unattended are not recommended or supported.

Building locally

If you want to make local modifications to these images for development purposes or just to customize the logic:

bash
git clone https://github.com/linuxserver/docker-modmanager.git
cd docker-modmanager
docker build \
  --no-cache \
  --pull \
  -t lscr.io/linuxserver/modmanager:latest .

The ARM variants can be built on x86_64 hardware and vice versa using lscr.io/linuxserver/docker-qemu-static

bash
docker run --rm --privileged lscr.io/linuxserver/docker-qemu-static --reset

Once registered you can define the dockerfile to use with -f Dockerfile.aarch64.

Versions

• 05.07.26: - Rebase to Alpine 3.24.
• 28.12.25: - Rebase to Alpine 3.23.
• 05.07.25: - Rebase to Alpine 3.22.
• 05.01.25: - Support multiple hosts.
• 22.12.24: - Initial Release.