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;

Other versions

# This example uses Nix-minecraft to declare a <version> NeoForge server called <name> 
services.minecraft-servers.<name>.package = pkgs.neoforgeServers.neoforge-<version>;

^{Note that the <version> is formatted as 26_1_2, 1_18_2, or 25w10a. Using a specific version could look like this: pkgs.vanillaServer.vanilla-1_8_9}

Nix-minecraft is a nix flakes based attempt at supporting a few more modded servers:

Server	*	Package name
Vanilla	Yes	vanillaServers.vanilla
Fabric	No	fabricServers.fabric
Quilt	No	quiltServers.quilt
Paper	Yes	paperServers.paper
Purpur	Yes	purpurServers.purpur
NeoForge	No	neoforgeServers.neoforge
Velocity	No	velocityServers.velocity

*Does it use the correct version of Java for Minecraft ≥26.1?

As stated above, since Minecraft 26.1, some packages use the wrong version of Java (presumably due to the change in Minecraft version formatting). To correct this, override with the appropriate version of Java.

# This example declares a 26.1 fabric server called <name>. Needing an override for java 25
services.minecraft-servers.<name>.package = pkgs.fabricServers.fabric-26_1.override 
{ jre_headless = pkgs.openjdk25_headless; };

Use a custom server.jar

Some mods like BTA! are not supported through previously explored methods. In that case running the server through the provided server.jar is an option (if one is provided).

^{Do note that doing this is not recommended, and should be seen as a last resort. Also if you really do not want to touch flakes.}

1. Download the server.jarMake sure to move the server.jar file inside a separate directory, or else it might spawn server files where you don't want them.
2. Install the appropriate version of Java .

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

3. Run the provided server.jar with java

   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

Prefer IPv4

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

See also

• nix-minecraft, a flake based attempt to better support Minecraft related content for the Nix ecosystem. It can be used for more complex server setups, including mods and plugins.
• https://exa.y2k.diy/garden/jvm-args for setting additional JVM flags in the jvmOpts option. Some server-related software—like the Velocity proxy—have their own recommended JVM flags list.
• https://mcuuid.net to get a player's UUID from their current username or vice versa.