host/tatos: configure prometheus

hosts/tatos/services/default.nix

@@ -2,10 +2,11 @@
 
 {
   imports = [
-    ./grafana
     ./miniflux
     ./wireguard
     ./nginx.nix
     ./dns.nix
+    ./grafana.nix
+    ./prometheus.nix
   ];
 }

hosts/tatos/services/prometheus.nix

@@ -0,0 +1,39 @@
+{ config, hostsPath, ... }:
+
+let
+  istalData = import (hostsPath + "/istal/data.secret.nix");
+  nodeExporterPort = 40000;
+in
+{
+  services.prometheus.exporters.node = {
+    enable = true;
+    port = nodeExporterPort;
+    # https://github.com/NixOS/nixpkgs/blob/nixos-24.05/nixos/modules/services/monitoring/prometheus/exporters.nix
+    enabledCollectors = [ "systemd" ];
+    # /nix/store/zgsw0yx18v10xa58psanfabmg95nl2bb-node_exporter-1.8.1/bin/node_exporter  --help
+    extraFlags = [ "--collector.ethtool" "--collector.softirqs" "--collector.tcpstat" "--collector.wifi" ];
+  };
+
+  # https://wiki.nixos.org/wiki/Prometheus
+  # https://nixos.org/manual/nixos/stable/#module-services-prometheus-exporters-configuration
+  # https://github.com/NixOS/nixpkgs/blob/nixos-24.05/nixos/modules/services/monitoring/prometheus/default.nix
+  services.prometheus = {
+    enable = true;
+    listenAddress = "127.0.0.1";
+    port = 33010;
+    globalConfig.scrape_interval = "15s"; # "1m"
+    scrapeConfigs = [
+      {
+        job_name = "node_dev";
+        static_configs = [
+          {
+            targets = [
+              "localhost:${toString nodeExporterPort}"
+              "${istalData.addr}:${toString nodeExporterPort}"
+            ];
+          }
+        ];
+      }
+    ];
+  };
+}