CLYZ Minecraft

A NixOS-powered project that concentrates on helping you develop, test and deploy a Minecraft service.

This project is initial used by the fellowship of CLYZ-OI, but you can also choose it as your Minecraft service solution.

Setup

Remotely

For a setup tutorial written in Chinese, please refer to this post.

If your remote host is not a NixOS system, you need to install it with official NixOS installer or NixOS-infect.

Using NixOS-infect is recommend, since it can transform your OS to NixOS automatically. If you'd like to use NixOS-infect, generate SSH key and push it to the remote machine:

ssh-keygen -t ed25519 # You may skip this step if you already prepared keys for it
ssh-copy-key root@example.com # Change the host address
ssh root@example.com

Now you should successfully login into the remote machine. Run the commands below:

curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect > nixos-infect
NIX_CHANNEL=nixos-unstable bash -x nixos-infect

Wait the SSH session terminated, and run the commands below to adjust hardware configurations:

scp root@example.com:/etc/nixos/hardware-configuration.nix hardware-configuration.nix

Clone this repository:

git clone https://github.com/clyz-oi/clyz-minecraft
cd clyz-minecraft

Replacing all lines started with boot or fileSystems in ./system/entry-points/production.nix with the corresponding occurrences in recently copied hardware-configuration.nix. The resulting configurations should look like this:

# ./system/entry-points/production.nix
{ config, lib, pkgs, ... }:

{
  imports = [
    ../.
  ];

  boot.loader.grub.device = "/dev/vda";

  boot.initrd.availableKernelModules = [ "ata_piix" "uhci_hcd" "xen_blkfront" "vmw_pvscsi" ];
  boot.initrd.kernelModules = [ "nvme" ];

  boot.tmp.cleanOnBoot = true;
  fileSystems."/" = { device = "/dev/vda1"; fsType = "ext4"; };
  zramSwap.enable = true;
}

Remember to change user configurations in ./system/default.nix, especially those related to SSH keys, otherwise you may not able to login into your server. Parts needed to be modify are presented below:

# ./system/default.nix
{ config, lib, pkgs, ... }:

{
  # ...
  networking.hostName = "your-server";
  
  users.users = {
    username = {
      isNormalUser = true;
      initialPassword = "";
      shell = pkgs.zsh;
      extraGroups = [ "wheel" "networkmanager" ];
      openssh.authorizedKeys.keys = [
        # Place your SSH public keys here
      ];
    };
  };

  users.users.root.openssh.authorizedKeys.keys = [
    # Place your SSH public keys here
  ];
  # ...
}

Run the following commands to finish the final deployment:

nix run nixpkgs#colmena apply
nix run nixpkgs#colmena exec reboot

The service minecraft-server.service should be running.

Locally

If you prefer local deployment, the above procedure just requires a slight change.

To apply changes, run the following command:

nix run nixpkgs#colmena apply-local --sudo

Keep in mind, never use nixos-rebuild.

Configration

All Minecraft-related configurations are located at ./system/service.nix. Search NixOS Options and ./modules/minecraft-server for services.minecraft-server.

If you'd like to change the server core, search NixOS Packages for existing ones or write your derivation (package).

Testing

Before push changes to remote, you can also test your configurations by launching a VM. Run the following command to do so:

nix run .#vm

You should enter a QEMU/KVM interface. Feel free to do any thing you want in this VM.

Note that you should never run nixos-rebuild switch --flake .#vm-clyz-minecraft because it uses totally different hardware configurations that are designed for VMs. The guest will mount the host's Nix Store as readonly filesystem. When applying it to the host, it will definitely break your system.

If you only want to test the server core, run the following command:

nix run .#minecraft-server