TerraHome/nixos/kubeadm/flake.nix

{
  description = "NixOS kubeadm cluster configs";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
  };

  outputs = { nixpkgs, ... }:
    let
      system = "x86_64-linux";
      lib = nixpkgs.lib;
      pkgs = nixpkgs.legacyPackages.${system};
      nodeNames = [ "cp-1" "cp-2" "cp-3" "wk-1" "wk-2" "wk-3" ];

      mkNode = {
        name,
        role,
        extraModules ? [ ],
      }:
        let
          roleModule = if role == "control-plane" then ./modules/k8s-control-plane.nix else ./modules/k8s-worker.nix;
          hardwarePath = ./hosts/hardware + "/${name}.nix";
        in
        nixpkgs.lib.nixosSystem {
          inherit system;
          modules = [
            ./modules/k8s-cluster-settings.nix
            ./modules/k8s-common.nix
            roleModule
            ({ lib, ... }: {
              imports = lib.optional (builtins.pathExists hardwarePath) hardwarePath;
              networking.hostName = name;
              system.stateVersion = "25.05";
              boot.loader.grub.devices = lib.mkDefault [ "/dev/sda" ];
              fileSystems."/" = lib.mkDefault {
                device = "/dev/disk/by-label/nixos";
                fsType = "ext4";
              };
            })
          ] ++ extraModules;
        };

      mkNodeByName = name:
        mkNode {
          inherit name;
          role = if lib.hasPrefix "cp-" name then "control-plane" else "worker";
        };

      mkEvalCheck = name:
        let
          cfg = mkNode {
            inherit name;
            role = if lib.hasPrefix "cp-" name then "control-plane" else "worker";
            extraModules = [
              ({ lib, ... }: {
                boot.loader.grub.devices = lib.mkDefault [ "/dev/sda" ];
                fileSystems."/" = lib.mkDefault {
                  device = "/dev/disk/by-label/nixos";
                  fsType = "ext4";
                };
              })
            ];
          };
        in
        pkgs.runCommand "eval-${name}" { } ''
          cat > "$out" <<'EOF'
          host=${cfg.config.networking.hostName}
          role=${if lib.hasPrefix "cp-" name then "control-plane" else "worker"}
          stateVersion=${cfg.config.system.stateVersion}
          EOF
        '';
    in {
      nixosConfigurations = lib.genAttrs nodeNames mkNodeByName;

      checks.${system} = lib.genAttrs nodeNames mkEvalCheck;
    };
}