Add adapter metrics service flags to 2.13 docs

Signed-off-by: Ali Aqel <[email protected]>

content/docs/2.13/operate/cluster.md

@@ -82,7 +82,7 @@ All applicable scalers will use this timeout. Setting a per-scaler timeout is cu
 
 ## HTTP connection disable keep alive
 
-Keep alive behaviour is enabled by default for every HTTP connection, this could stack a huge amount of connections (one per scaler) in some scenarios. 
+Keep alive behaviour is enabled by default for every HTTP connection, this could stack a huge amount of connections (one per scaler) in some scenarios.
 
 You can disable keep alive for every HTTP connection by adding the relevant environment variable to both the KEDA Operator, and KEDA Metrics Server deployments:
 
@@ -128,6 +128,16 @@ The Kubernetes client config used within KEDA Operator and KEDA Metrics Adapter
 | kube-api-burst      | cfg.Burst               | 30            | Set the burst for throttling requests sent to the apiserver    |
 | disable-compression | cfg.DisableCompression  | true          | Disable compression for response in k8s restAPI in client-go, see [this Kubernetes issue](https://github.com/kubernetes/kubernetes/issues/112296) for details |
 
+## Metrics Service Parameters
+
+The Metrics Service config used by the KEDA Metrics Adapter to connect to the KEDA Operator can be adjusted by passing the following command-line flags to the Adapter binary:
+
+|     Adapter Flag                    | Default Value                                     | Description                                    |
+| ----------------------------------- | ------------------------------------------------- | ---------------------------------------------- |
+| metrics-service-address             | keda-operator.keda.svc.cluster.local:9666         | The address of the GRPC Metrics Service Server |
+| metrics-service-grpc-authority      | ""                                                | Host Authority override for the Metrics Service if the Host Authority is not the same as the address used for the GRPC Metrics Service Server. |
+
+
 ## Configure `MaxConcurrentReconciles` for Controllers
 
 To implement internal controllers KEDA uses the [controller-runtime project](https://github.com/kubernetes-sigs/controller-runtime), that enables configuration of [MaxConcurrentReconciles property](https://pkg.go.dev/sigs.k8s.io/controller-runtime/pkg/controller#Options), ie. the maximum number of concurrent reconciles which can be run for a controller.