hosts/monitoring-3: add monitoring of mercury

hosts/hydra-1/configuration.nix

@@ -54,7 +54,7 @@
     bindAddress = "127.0.0.1";
     secretKeyFile = "/var/src/secrets/nix-serve/secret-key.key";
     # Workaround https://github.com/NixOS/nix/issues/7704#issuecomment-1409480909
-    package = pkgs.nix-serve.override {
+    package = pkgs.nix-serve-ng.override {
       nix = pkgs.nixVersions.nix_2_12;
     };
   };
@@ -80,7 +80,7 @@
         '';
       };
       locations."/" = {
-        proxyPass = "http://localhost:5005";
+        proxyPass = "http://127.0.0.1:5005";
       };
     };
   };

hosts/monitoring-3/prometheus.nix

@@ -13,6 +13,15 @@ let
         nixos = false;
       };
     };
+    "mercury".config = {
+      networking.hostName = "mercury";
+      clerie.monitoring = {
+        enable = true;
+        id = "401";
+        pubkey = "jrwc4gMZh/Ss1MEXWkLhXcAp4Z++Xnl4noYIZnCfWQg=";
+        nixos = false;
+      };
+    };
   };
 
   monitoringHosts = filterAttrs (name: host: