Valheim Dedicated Server in Docker

A Valheim dedicated server containerized into a Docker container for portable deployment.

Preface

The purpose of this repository is to build and run a container for a Valheim dedicated server.

Building the container

In order to build the container, the easiest way to get started is to use the docker compose tool. Lever the docker compose command to build the dedicated server container so it is ready to be used. Sometimes you may have to bust the cache if a new version of the server is released but the Dockerfile is not changed. This can be accomplished by adding the --no-cache flag.

# Use docker compose and build the container.
> docker compose build

# Create initial container but don't start it.
> docker compose up --no-start
Creating valheim_server_1 ... done

# Check that the image exists.
> docker compose images

   Container         Repository      Tag       Image Id      Size
------------------------------------------------------------------
valheim_server_1   valheim_server   latest   00164016873a   1.7 GB

Creating and configuring the data volume(s)

In order for any worlds or save game data to persist, we need a volume. There are many ways to go about adding a persistent volume to your server but this document will only go over the docker volume method.

If you are using the docker-compose.yml file included with this repository, then all you have to do to prepare the data volume (if it doesn't already exist) is to bring up a container with a simple run. The entrypoint.sh script will take care of ensuring proper ownership of the data files.

Running the dedicated server

The first thing you should do is ensure the environment is customized to your needs to do things like set the world name, world seed, password and other options.

Configuring environment and settings

export VALHEIM_SERVER_NAME="Valheim"
export VALHEIM_SERVER_WORLD="watermelons"
export VALHEIM_SERVER_PASSWORD="fruity"

Now that you've configured your environment, bring the dedicated server container up. Simply use the docker compose up command and it will bootstrap.

If you have specified a world name and seed that does not exist in the data files yet, it will be generated by the game. Optionally, you may also copy an existing world into the docker data volume (both .fwl and .db). Just be sure to stop the server and then update the $VALHEIM_SERVER_WORLD above to reflect the name of the world files in the data directory worlds_local/ of the dedicated server data volume. You MUST copy both the .fwl and .db files and the filenames are case-sensitive!

# Attached console mode.
docker compose up server

# Detatched console mode.
docker compose up -d server

You can then shut down the server gracefully by sending a SIGINT/SIGTERM. If running in foreground or console mode a Ctrl+C should invoke this. If you run docker compose stop server, then that will stop it gracefully for you.

Test server

The compose file also contains a server definition for a test instance of Valheim dedicated server. This is useful for testing or canary changes to the game server, configuration, mods, etc. By default it is commented out in the compose file. This means if you end up utilizing it or creating a test instance of the server that docker compose may complain about orphaned images or containers. These can be ignored.