Originally published on Notion.

This article is the one originally posted with a few markup changes, spelling and grammatical fixes.

Sometimes you just need to make a process a daemon. This is especially useful when you want to have a game server running constantly, but don’t want a tmux session perpetually existing. Not to mention, when reboot time comes, the server needs to be fully restarted again.

Most Linux distributions nowadays use an init program called systemd, this program is meant to start up the system and its services. systemd does so much more but it’s irrelevant here.

If you don’t have systemd, you either have an older Linux distribution or you clearly know what you are doing.

We’ll be using a vanilla Minecraft server as an example.

And with the intro out of the way, let’s start.

The Service Account

Before we make the game server a service, it’s a good idea to separate the server out into its own user account. You can create a new system account by using the following command line:

sudo useradd minecraft -r -m -s /sbin/nologin

The command above creates a new user account (useradd) called “minecraft”, which is a system account (-r) without a login shell (-s /sbin/nologin) and a home folder (-m).

You can then copy the server executables and config files over to that user account’s home folder (usually /home/{username}). To run commands as that user, log in as the service account and navigate to its home folder:

sudo -u minecraft bash -l
cd ~

Lastly it’s a good idea to create a shell script which starts the server. This is useful in the case of a Minecraft server since it runs on top of Java and we can pass flags to it easily.

Example wrapper script

#!/bin/sh
java -Xmx1024M -Xms1024M -jar server.jar nogui

Write a script with the arguments your game server needs and make it executable with

chmod 755 start.sh
./start.sh

Give it a test and see if it runs before we make it a server. Make sure you do most of your config now since you might not have access to the server prompt after we make it a service.

The Unit File

systemd uses “unit files” to describe services. Unit files are kept in /etc/systemd/system — we’ll be creating minecraft.service:

Example unit file

[Unit]
Description=Minecraft Server
After=network.target

[Service]
Type=simple
User=minecraft
WorkingDirectory=/home/minecraft
ExecStart=/home/minecraft/start.sh
Restart=always

[Install]
WantedBy=multi-user.target

The file above describes a unit called “Minecraft Server” (Description=Minecraft Server), which loads after the computer connects to a network (After=network.target).

This unit manages a simple service which runs as the user “minecraft” and runs the start script we made in the home folder. The server will always restart if it’s stopped without user control.

For more information you can consult the systemd.service(5) man page.

Starting the Service

To start the systemd service, you will need to run:

sudo systemctl start minecraft.service

This will continue running the server until your computer shuts down or restarts. If you want the game server to start with the computer, you will need to run:

sudo systemctl enable minecraft.service

And that’s it.