Add k3s module, and enable for penguin

modules/nixos/my_k3s/default.nix

@@ -0,0 +1,49 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.my_k3s;
+  inherit (lib) mkEnableOption mkIf mkOption;
+  types = lib.types;
+in
+{
+  options.my_k3s = {
+    enable = mkEnableOption "My k3s cluster";
+    tokenFile = mkOption {
+      type = types.nonEmptyStr;
+    };
+    role = mkOption {
+      type = types.nonEmptyStr;
+      default = "server";
+    };
+    clusterInit = mkOption {
+      type = types.bool;
+      default = false;
+    };
+    serverAddr = mkOption {
+      type = types.nonEmptyStr;
+      default = "server";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services.k3s = {
+      enable = true;
+      role = cfg.role;
+      tokenFile = cfg.tokenFile;
+      clusterInit = cfg.clusterInit;
+      serverAddr = cfg.serverAddr;
+    };
+    environment.systemPackages = [ pkgs.nfs-utils ];
+    services.openiscsi = {
+      enable = true;
+      name = "iqn.2016-04.com.open-iscsi:${config.networking.hostName}";
+    };
+    systemd.tmpfiles.rules = [
+      "L+ /usr/local/bin - - - - /run/current-system/sw/bin/"
+    ];
+  };
+}