DayZDockerServer

A Linux DayZ server in a Docker container. The main script's functionality is derived from this project. That functionality is described here. The goal is to reproduce some of that functionality but also add more features.

The main goal is to provide a turnkey DayZ server with mod support that can be spun up with as little as a machine running Linux with Docker and Docker Compose installed.

This project started when the Linux DayZ server was released for DayZ experimental version 1.14 on 09/02/2021. As of 02/20/2024, there is now an official Linux DayZ server, but...

Caveats

• Some mods are known to crash the server on startup:
  • DayZ Expansion AI
  • Red Falcon Flight System Heliz - Bug report here
• Some mods work, but have bugs:
  • DayZ Expansion Groups
    • The save file becomes corrupted and when the server restarts so the changes do not persist.
• There are other bugs:
  • Server doesn't stop with SIGTERM
• After deleting the serverfiles docker volume, permissions are incorrect when restarting the stack, which causes file permissions errors. To fix:

docker compose run -u0 --rm web chown user:user /serverfiles -R

Unfortunately, this cannot be easily mitigated within the code, so it remains a manual process.

This project is a work in progress: See the roadmap.

Configure and Build

Ensure Docker and Docker compose are properly installed. This means setting it up so it runs as your user. Make sure you're running these commands as your user, in your home directory.

Clone the repo, and change into the newly created directory:

git clone https://ceregatti.org/git/daniel/dayzdockerserver.git
cd dayzdockerserver

Create a .env file that contains your user id. Usually the ${UID} shell variable has this:

echo "export USER_ID=${UID}" | tee .env

Build the Docker images:

docker compose build

Steam Integration

SteamCMD is used to manage Steam downloads. A vanilla DayZ server can be installed with the anonymous Steam user, but most mods cannot. If the goal is to add mods, a real Steam login must be used. Login:

docker compose run --rm web dz login

Follow the prompts. Hit enter to accept the default, which is to use the anonymous user, otherwise use your real username and keep following the prompts to add your password. If you have Steam Guard (which you really should have), it will wait for the request to be approved on your phone. The process will wait until it's approved.

The credentials will be managed by SteamCMD. This will store a session token in the homedir docker volume. All subsequent SteamCMD commands will use this. so this process does not need to be repeated unless the session expires or the docker volume is deleted.

To manage the login credentials, simply run the above command again. See Manage.

Install

The base server files must be installed before the server can be run:

docker compose run --rm web dz install

This will download about 3 Gigabytes of files.

Run

Copy files/serverDZ.cfg.example to serverDZ.cfg in the files directory:

cp files/serverDZ.cfg.example file/serverDZ.cfg

This file will be used by the server within the container. Set the values of any variables there. See the documentation if you want, but most of the default values are fine. The Chernarus map is set by default in this file. Edit the file, and at the very least change the server name:

hostname = "Something other than Server Name";   // Server name

Install the server config file:

docker compose run --rm server dz config

The maintenance of the config file is a work in progress. The goal is to create a facility for merging changes into the config file and maintain a paper trail of changes. For now, just remember that the working config file is the one that was copied into the root of the project, and that changes to it must be copied into the container using the command above.

This only has to be done initially or when changes are made to serverDZ.cfg.

Up

Launch the stack into the background:

docker compose up -d

There will be nothing in mpmissions when the server container starts for the first time. A pristine copy of dayzOffline.chernarusplus will be copied from the mpmission volume to the server container. This will be the default map. To install other maps, see Maps.

To see the server log:

docker compose logs -f server

Stopping the server

To stop the DayZ server:

docker compose exec server dz stop

If it exits cleanly, the container will also stop. Otherwise a crash is presumed and the server will restart. Ideally, the server would always exit cleanly, but... it's DayZ.

To stop the containers:

docker compose stop

To bring the entire stack down:

docker compose down

Since all files are maintained within docker volumes, all changes persist when bringing the stack down.

Manage

Maps

Installing another map requires installing its mod and mpmissions files. Some maps maintain github repositories or public web sites for their mpmissions, while others do not. This project aims to support DayZ maps whose mpmissions are easily accessible "Out of the box" by maintaining configuration files for them.

RCON

A terminal-based RCON client is included: https://github.com/indepth666/py3rcon. The dz script manages what's necessary to configure and run it:

The following command presumes the server has been brought up (otherwise RCON can't connect to anything):

docker compose exec server dz rcon

To reset the RCON password in the Battle Eye configuration file, simply delete it, and a random one will be generated on the next server startup:

docker compose run --rm server rm serverfiles/battleye/baserver_x64_active*

Don't expect much from this RCON at this time.

Update the DayZ server files

It's probably not a good idea to update the server files while a server is running. Bring everything down first:

docker compose down

Then run the command:

docker compose run --rm web dz update

This will update the server base files as well as all installed mods.

Don't forget to bring it back up.

Stop the DayZ server

To stop the server:

docker compose exec server dz stop

The above sends the SIGINT signal to the server process. The server sometimes fails to stop with this signal. It may be necessary to force stop it with the SIGKILL:

docker compose exec server dz force

When the server exits cleanly, i.e. exit code 0, the container also stops. Otherwise, a crash is presumed, and the server will be automatically restarted.

To bring the entire stack down:

docker compose down

Workshop - Add / List / Remove / Update mods

Interactive interface for managing mods. These commands are run with the stack being up.

# Adding and removing of mods is done in the web container. These commands only download, list, update, or remove mods to/from volumes that are shared by the web and server containers.
docker compose exec web dz (a)dd id | (l)ist | (m)odupdate | (r)emove id
# Once added to the web container, activate any of the installed mods in the running server. Activated mods are also deactivated here.
docker compose exec server dz (a)ctivate id [ id2 [ id3 ]] | (d)eactivate id [ id2 [ id3 ]] | (l)ist | (s)tatus

Look for mods in the DayZ Workshop. Browse to one. In its URL will be an id parameter. Here is the URL to Community Framework, a mod that is a dependency of many other mods (but by itself really doesn't do anything): https://steamcommunity.com/sharedfiles/filedetails/?id=1559212036. To add it:

docker compose exec web dz add 1559212036

Then activate it in the server container:

docker compose exec server dz activate 1559212036

Activating (or deactivating) mods will add (or remove) their names from the -mod= parameter in the server command line.

To avoid re-downloading large mods, the activate and deactivate server container commands will simply disable the mod but keep its files. Note that mod updates will also update deactivated mods.

The above is a bad example, as Community Framework doesn't really do anything by itself, but is a dependency of pretty much every admin mod. Add VPPAdminTools too:

docker compose exec web dz add 1828439124
docker compose exec shell dz activate 1828439124

Read the instructions on the page of the URL above to add yourself as an admin to your server.

Looking under the hood

All the server files persist in a docker volume that represents the container's unprivileged user's home directory. Open a bash shell in the running container:

docker compose exec web bash

Or open a shell into a new container if the docker stack is not up:

docker compose run --rm web bash

All the files used by the server are in a docker volume. Any change made will be reflected upon the next container startup.

Use this shell cautiously.

Development mode

Add the following to the .env file:

export DEVELOPMENT=1

Bring the stack down then back up. Now, instead of the server starting when the server container comes up it will simply block, keeping both the web and server containers up and accessible.

This allows access to the server container using exec. You can then start and stop the server manually, using dz:

# Go into the server container
docker compose exec shell bash
# See what the server status is
dz s
# Start it
dz start

To stop the server, hit control c.

Caveat: Some times the server doesn't stop with control c. If that's the case, control z, exit, then dz f. YMMV.

TODO

• Create web management tool:
  • It shells out to dz (for now) for all the heavy lifting.
• Create some way to send messages to players on the server using RCON.
• Implement multiple ids for mod commands. (In progress)
• Fix the permissions bug listed in caveats.