services: prometheus: restructure a bit, extract node-exporter

Signed-off-by: Christoph Heiss <christoph@c8h4.io>

machines/fort.nix

@@ -27,6 +27,7 @@ in {
     ../services/fail2ban.nix
     ../services/matrix-hookshot.nix
     ../services/nginx.nix
+    ../services/node-exporter.nix
     ../services/web/c8h4-io.nix
     ../system/virtual-machine.nix
   ];

machines/tank.nix

@@ -11,6 +11,7 @@
     ../services/home-assistant.nix
     ../services/navidrome.nix
     ../services/nginx.nix
+    ../services/node-exporter.nix
     ../services/paperless.nix
     ../services/postgresql.nix
     ../services/prometheus.nix
@@ -108,4 +109,10 @@
     listenAddress = "[::1]:8000";
     appendOnly = true;
   };
+
+  services.prometheus.exporters.zfs = {
+    enable = true;
+    listenAddress = "[::1]";
+    extraFlags = [ "--collector.dataset-snapshot" ];
+  };
 }

services/node-exporter.nix

@@ -0,0 +1,34 @@
+{ config, lib, ... }:
+
+let
+  inherit (lib) mkOption types;
+  cfg = config.my.services.node-exporter;
+in {
+  options.my.services.node-exporter = {
+    listenAddress = mkOption {
+      type = types.str;
+      default = "[::1]";
+      description = "Address to listen on.";
+    };
+  };
+
+  config = {
+    services.prometheus.exporters.node = {
+      enable = true;
+      inherit (cfg) listenAddress;
+      enabledCollectors = [ "systemd" ];
+      # disable a whole bunch of useless/unneeded collectors
+      disabledCollectors = [
+        "arp"
+        "bcache"
+        "bonding"
+        "fibrechannel"
+        "infiniband"
+        "ipvs"
+        "selinux"
+        "tapestats"
+        "xfs"
+      ];
+    };
+  };
+}

services/prometheus.nix

@@ -1,47 +1,17 @@
-{ config, my, secrets, ... }:
+{ my, secrets, ... }:
 
-let
-  nodeExporter = config.services.prometheus.exporters.node;
-  zfsExporter = config.services.prometheus.exporters.zfs;
-in {
+{
   services.prometheus = {
     enable = true;
     checkConfig = "syntax-only";
     webExternalUrl = "http://${my.homelab.fqdn}/prometheus";
     listenAddress = "[::1]";
-    exporters = {
-      node = {
-        enable = true;
-        listenAddress = "[::1]";
-        enabledCollectors = [ "systemd" ];
-        # disable a whole bunch of useless/unneeded collectors
-        disabledCollectors = [
-          "arp"
-          "bcache"
-          "bonding"
-          "fibrechannel"
-          "infiniband"
-          "ipvs"
-          "selinux"
-          "tapestats"
-          "xfs"
-          "zfs" # we got the dedicated zfs-exporter instead
-        ];
-      };
-      zfs = {
-        enable = true;
-        listenAddress = "[::1]";
-        extraFlags = [ "--collector.dataset-snapshot" ];
-      };
-    };
     scrapeConfigs = [
       {
         job_name = "zfs-exporter";
         scrape_interval = "60s";
-        static_configs = [{
-          targets =
-            [ "${zfsExporter.listenAddress}:${toString zfsExporter.port}" ];
-        }];
+        static_configs =
+          [{ targets = [ "tank:${toString my.services.zfs-exporter.port}" ]; }];
         # https://github.com/pdf/zfs_exporter/issues/24#issuecomment-1616802017
         metric_relabel_configs = [
           {
@@ -61,8 +31,10 @@ in {
       {
         job_name = "node-exporter";
         static_configs = [{
-          targets =
-            [ "${nodeExporter.listenAddress}:${toString nodeExporter.port}" ];
+          targets = map (x: "${x}:${toString my.services.node-exporter.port}") [
+            "fort"
+            "tank"
+          ];
         }];
       }
       {
@@ -72,15 +44,15 @@ in {
         metrics_path = "/api/prometheus";
         authorization.credentials_file =
           secrets.homeassistant-prometheus-token.destination;
-        scheme = "https";
-        static_configs =
-          [{ targets = [ my.homelab.services.homeassistant.host ]; }];
+        static_configs = [{
+          targets = [ "tank:${toString my.services.home-assistant.port}" ];
+        }];
       }
       {
         job_name = "openwrt-exporter";
         scrape_interval = "30s";
         scheme = "https";
-        static_configs = [{ targets = [ my.homelab.services.openwrt.host ]; }];
+        static_configs = [{ targets = [ my.machines.wort.host ]; }];
       }
     ];
   };