[user module] add backup usr

machines/modules/malobeo/users.nix

@@ -8,12 +8,17 @@ in
     malobeo = lib.mkOption {
       type = lib.types.bool;
       default = true;
-      description = "enable malobeo user, defaults to on";
+      description = "enable malobeo user, defaults to on, ";
     };
     admin = lib.mkOption {
       type = lib.types.bool;
       default = true;
-      description = "enable admin user, defaults to on to prevent lockouts";
+      description = "enable admin user, defaults to on to prevent lockouts, passwordless sudo access";
+    };
+    backup = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = "enable backup user, ";
     };
   };
   config = lib.mkMerge [
@@ -48,6 +53,26 @@ in
         }
       ];
     })
+    (lib.mkIf cfg.backup {
+      users.users.backup = {
+        isNormalUser = true;
+        hashedPassword = null;
+        openssh.authorizedKeys.keys = sshKeys.backup;
+        description = "backup user for pull style backups, can only use zfs commands";
+      };
+      environment.systemPackages = with pkgs; [];
+      security.sudo.extraRules = [
+        {
+          users = [ "backup" ];
+          commands = [
+            {
+              command = "${pkgs.zfs-user}/bin/zfs";
+              options = [ "NOPASSWD" ];
+            }
+          ];
+        }
+      ];
+    })
     {
       users.mutableUsers = false;
       environment.systemPackages = with pkgs; [