add monitoring

config/monitoring/prometheus.nix

@@ -0,0 +1,40 @@
+{config, ...}: {
+  services.prometheus = {
+    enable = true;
+    port = 9100;
+    globalConfig.scrape_interval = "1m";
+    scrapeConfigs = [
+      {
+        job_name = "node";
+        static_configs = [
+          {
+            targets = [
+              "localhost:${
+                toString
+                config.services.prometheus.exporters.node.port
+              }"
+            ];
+          }
+        ];
+      }
+    ];
+
+    exporters = {
+      node = {
+        enable = true;
+        port = 9101;
+        enabledCollectors = [
+          "ethtool"
+          "softirqs"
+          "systemd"
+          "tcpstat"
+          "wifi"
+        ];
+        extraFlags = [
+          "--collector.ntp.protocol-version=4"
+          "--no-collector.mdadm"
+        ];
+      };
+    };
+  };
+}