feat: better prometheus integration

modules/nixos/prometheus.nix

@@ -32,15 +32,16 @@ in
       }
     '';
     services.restic.server.prometheus = cfg.enable;
-    services.gotosocial.settings = {
-      metrics-enable = true;
+    services.gotosocial.settings = mkIf cfg.enable {
+      metrics-enabled = true;
     };
     services.prometheus = mkIf cfg.enable {
       enable = true;
       port = 9091;
       globalConfig.external_labels = { hostname = config.networking.hostName; };
       remoteWrite = mkIf cfg.grafana.enable [
-        { name = "grafana";
+        {
+          name = "grafana";
           url = "https://prometheus-prod-24-prod-eu-west-2.grafana.net/api/prom/push";
           basic_auth = {
             username = "1340065";
@@ -51,22 +52,118 @@ in
       exporters = {
         node = {
           enable = true;
-          enabledCollectors = [ "systemd" ];
+          enabledCollectors = [
+            "conntrack"
+            "diskstats"
+            "entropy"
+            "filefd"
+            "filesystem"
+            "loadavg"
+            "meminfo"
+            "netdev"
+            "netstat"
+            "stat"
+            "time"
+            "vmstat"
+            "systemd"
+            "logind"
+            "interrupts"
+            "ksmd"
+          ];
           port = 9100;
         };
       };
       scrapeConfigs = [
-        { job_name = "prometheus";
+        {
+          job_name = "prometheus";
           static_configs = [
             { targets = [ "localhost:${toString config.services.prometheus.port}" ]; }
           ];
         }
-        { job_name = "node";
+        {
+          job_name = "node";
           static_configs = [
             { targets = [ "localhost:${toString config.services.prometheus.exporters.node.port}" ]; }
           ];
         }
       ];
+
+      alertmanager = {
+        enable = true;
+        listenAddress = "127.0.0.1";
+        extraFlags = [
+          "--cluster.advertise-address=127.0.0.1:9093"
+        ];
+        configuration = {
+          route = {
+            receiver = "ntfy";
+          };
+          receivers = [
+            {
+              name = "ntfy";
+              webhook_configs = [
+                {
+                  url = "https://ntfy.xinyang.life/prometheus-alerts";
+                  send_resolved = true;
+                }
+              ];
+            }
+          ];
+        };
+      };
+
+      alertmanagers = [
+        {
+          scheme = "http";
+          path_prefix = "/alertmanager";
+          static_configs = [
+            {
+              targets = [
+                "${config.services.prometheus.alertmanager.listenAddress}:${toString config.services.prometheus.alertmanager.port}"
+              ];
+            }
+          ];
+        }
+      ];
+
+      rules = [
+        ''
+          groups:
+            - name: system_alerts
+              rules:
+                - alert: SystemdFailedUnits
+                  expr: node_systemd_unit_state{state="failed"} > 0
+                  for: 5m
+                  labels:
+                    severity: critical
+                  annotations:
+                    summary: "Systemd has failed units on {{ $labels.instance }}"
+                    description: "There are {{ $value }} failed units on {{ $labels.instance }}. Immediate attention required!"
+
+                - alert: HighLoadAverage
+                  expr: node_load1 > 0.8 * count without (cpu) (node_cpu_seconds_total{mode="idle"})
+                  for: 1m
+                  labels:
+                    severity: warning
+                  annotations:
+                    summary: "High load average detected on {{ $labels.instance }}"
+                    description: "The 1-minute load average ({{ $value }}) exceeds 80% the number of CPUs."
+
+                - alert: HighTransmitTraffic
+                  expr: rate(node_network_transmit_bytes_total{device!="lo"}[5m]) > 100000000
+                  for: 1m
+                  labels:
+                    severity: warning
+                  annotations:
+                    summary: "High network transmit traffic on {{ $labels.instance }} ({{ $labels.device }})"
+                    description: "The network interface {{ $labels.device }} on {{ $labels.instance }} is transmitting data at a rate exceeding 100 MB/s for the last 1 minute."
+        ''
+        (if config.services.restic.server.enable then
+          ''
+            groups:
+              - name: restic_alerts
+          '' else "")
+      ];
     };
   }
     {
@@ -90,6 +187,5 @@ in
           ];
         })
       ];
-  }
-  ]);
+    }]);
 }