Add monitoring and metrics

modules/monitoring-exporters.nix

@@ -0,0 +1,61 @@
+{ config, lib, ... }:
+{
+  services.prometheus = {
+    exporters = {
+      node = {
+        enable = true;
+        enabledCollectors = [ "systemd" "processes" ];
+      };
+    };
+  };
+
+  services.promtail = {
+    enable = true;
+    configuration = {
+      server = {
+        http_listen_port = 3101;
+        grpc_listen_port = 0;
+      };
+      clients = [{
+        url = "http://10.0.2.3:3100/loki/api/v1/push";
+      }];
+      scrape_configs = [
+        {
+          job_name = "journal";
+          journal = {
+            max_age = "12h";
+            labels = {
+              job = "systemd-journal";
+              host = "${config.networking.hostName}";
+            };
+          };
+          relabel_configs = [{
+            source_labels = [ "__journal__systemd_unit" ];
+            target_label = "unit";
+          }];
+        }
+        (lib.mkIf config.services.nginx.enable {
+          job_name = "nginx";
+          static_configs = [
+            {
+              targets = [ "localhost" ];
+              labels = {
+                job = "nginx";
+                host = "${config.networking.hostName}";
+                __path__ = "/var/log/nginx/*.log";
+              };
+            }
+          ];
+        })
+      ];
+    };
+  };
+
+  systemd.services.promtail.serviceConfig = {
+    ReadOnlyPaths = lib.mkIf config.services.nginx.enable "/var/log/nginx";
+    SupplementaryGroups = lib.mkIf config.services.nginx.enable [ "nginx" ];
+  };
+}
+
+
+