update docs

Author: razvan

docs/modules/spark-k8s/pages/usage-guide/history-server.adoc

@@ -157,10 +157,9 @@ By setting up port forwarding on 18080 the UI can be opened by pointing your bro
 
 image::history-server-ui.png[History Server Console]
 
-== Metrics
+== Monitoring
 
-[NOTE]
-====
-Starting with version 25.7, the built-in Prometheus servlet is enabled in addition to the existing JMX exporter.
-The JMX exporter is still available but it is deprecated and will be removed in a future release.
-====
+The operator creates a Kubernetes service dedicated specifically to collect metrics for Spark History instances with Prometheus.
+These metrics are exported via the JMX exporter as the history server doesn't support the built in Spark prometheus servlet.
+The service name follows the convention `<stacklet name>-history-metrics`.
+Metrics can be scraped at the endpoint `<service name>:18081/metrics`.

docs/modules/spark-k8s/pages/usage-guide/operations/applications.adoc

@@ -9,7 +9,7 @@ As the operator creates the necessary resources, the status of the application t
 NOTE: The operator never reconciles an application once it has been created.
 To resubmit an application, a new SparkApplication resource must be created.
 
-== Metrics
+== Monitoring
 
 [NOTE]
 ====

docs/modules/spark-k8s/pages/usage-guide/spark-connect.adoc

@@ -26,12 +26,14 @@ include::example$example-spark-connect.yaml[]
 <7> Customize the driver properties in the `server` role. The number of cores here is not related to Kubernetes cores!
 <8> Customize `spark.executor.\*` and `spark.kubernetes.executor.*` in the `executor` role.
 
-== Metrics
+== Monitoring
 
-The server pod exposes Prometheus metrics at the following endpoints:
+The operator creates a Kubernetes service dedicated specifically to collect metrics for Spark Connect instances with Prometheus.
+The service name follows the convention `<stacklet name>-server-metrics`.
+This service exposes Prometheus metrics at the following endpoints:
 
-* `/metrics/prometheus` for driver instances.
-* `/metrics/executors/prometheus` for executor instances.
+* `<service name>:4040/metrics/prometheus` for driver instances.
+* `<service name>:4040/metrics/executors/prometheus` for executor instances.
 
 To customize the metrics configuration use the `spec.server.configOverrides' like this:
 
@@ -47,8 +49,8 @@ The example above adds a new endpoint for application metrics.
 
 == Spark History Server
 
-Unforunately integration with the Spark History Server is not supported yet.
-The connect server seems to ignore the `spark.eventLog` properties while also prohibiting clients to set them programatically.
+Unfortunately integration with the Spark History Server is not supported yet.
+The connect server seems to ignore the `spark.eventLog` properties while also prohibiting clients to set them programmatically.
 
 == Notable Omissions