Minecraft Server

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Disambiguation: Not to be confused with the Minecraft client.

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Tip: This package is unfree, and will require extra steps to install. You can read more about allowing unfree software in the Nixpkgs Manual.

Minecraft Server is a server for the sandbox game Minecraft. Currently, only servers for the Java Edition of Minecraft are supported.

Setup

The minimum example to have a Minecraft server running on localhost at the default port of 25565. By setting the eula option to true, you are agreeing to the Minecraft EULA.

❄︎ /etc/nixos/configuration.nix

services.minecraft-server.enable = true;
services.minecraft-server.eula = true;

Configuration

This example is a more thorough declarative configuration that sets a few options including opening the firewall, restricting the server to only whitelisted users and setting the port to 43000.

❄︎ /etc/nixos/configuration.nix

services.minecraft-server = {
  enable = true;
  eula = true;
  openFirewall = true; # Opens the port the server is running on (by default 25565 but in this case 43000)
  declarative = true;
  whitelist = {
    # This is a mapping of Minecraft usernames to to the players' UUIDs
    username1 = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
    username2 = "yyyyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy";
  };
  serverProperties = {
    server-port = 43000;
    difficulty = 3;
    gamemode = 1;
    max-players = 5;
    motd = "NixOS Minecraft server!";
    white-list = true;
    allow-cheats = true;
  };
  jvmOpts = "-Xms2048M -Xmx2048M"; 
};

You might want to view the list of all available server properties for the vanilla server.

See #See also for recommended JVM flags for the jvmOpts option. These primarily depend on your Java version.

Tips and tricks

Accessing the Minecraft server console

The Minecraft server console allows you to view server logs and issue commands to the server interactively. The Minecraft server console is not directly accessible on NixOS—unlike on non-declarative systems, where running the server through a shell command provides the interactive console to the current terminal.

Accessing logs

Since the Minecraft server runs as a systemd service, you can access its stdout through the systemd journal:

journalctl -eu minecraft-server.service

The logs are also available in the logs subdirectory of the server's data directory, which is configured via services.minecraft-server.dataDir. The default value for this option is /var/lib/minecraft.

Issuing commands

There are two ways to issue commands to the Minecraft server:

1. Writing to the server’s stdin via its named pipe at /run/minecraft-server.stdin:

echo "say Removed Herobrine" > /run/minecraft-server.stdin

2. Using the server's provided RCON feature.

Example minimal configuration:

❄︎ /etc/nixos/configuration.nix

 services.minecraft-server.serverProperties = {
    enable-rcon = true;
    "rcon.password" = "your password";
 };

Use a different server

To use a specific server version, or another Minecraft server—such as PaperMC—change services.minecraft-server.package to a nix package that represents your desired server.

For example:

services.minecraft-server.package = pkgs.minecraftServers.vanilla-1-12;

or

services.minecraft-server.package = pkgs.papermc;

Prefer IPv4

To use IPv4 by default, add -Djava.net.preferIPv4Stack=true to jvmOpts.

Server.jar

Some mods like Fabric or BTA!, that might not be available through nixpkgs, provide their own server.jar files.

^{Make sure to move the server.jar file inside a separate directory, or else it might spawn server files where you don't want them.}

Server.jar dependencies

In order to run server.jar (or any jar file in general), you will need to install the appropriate version of Java .

pkgs.jdkX # replace the 'X' with the correct java version number here

Then just run the server.jar file and append optional JVM flags

java -Xmx4G -jar /path/to/server.jar -nogui

The -Xmx flag sets the max memory allocation (here 4GB). The -nogui flag disables the minecraft server gui