monitor kestra with prometheus alerts

hosts/AZ-PRM-1/services/containers/kestra.nix

@@ -1,6 +1,7 @@
 {config, ...}: let
   serviceName = "kestra";
   servicePort = config.m3ta.ports.get serviceName;
+  metricsPort = config.m3ta.ports.get "kestra-metrics";
 in {
   virtualisation.oci-containers.containers."${serviceName}" = {
     image = "docker.io/kestra/kestra:latest";
@@ -9,7 +10,10 @@ in {
       config.age.secrets.kestra-secrets.path
     ];
     cmd = ["server" "standalone" "--config" "/etc/config/application.yaml"];
-    ports = ["127.0.0.1:${toString servicePort}:8080"];
+    ports = [
+      "127.0.0.1:${toString servicePort}:8080"
+      "127.0.0.1:${toString metricsPort}:8081"
+    ];
     user = "root";
     volumes = [
       "/var/run/podman/podman.sock:/var/run/docker.sock"