Update content/docs/2.9/operate/prometheus.md

Signed-off-by: dariox <9934402+darox@users.noreply.github.com>

content/docs/2.9/operate/prometheus.md

@@ -6,7 +6,7 @@ weight = 200
 
 ## Prometheus Exporter Metrics
 
-### Operator 
+### Operator
 
 The KEDA Operator exposes Prometheus metrics which can be scraped on port `8080` at `/metrics`. The following metrics are being gathered:
 
@@ -16,11 +16,30 @@ The KEDA Operator exposes Prometheus metrics which can be scraped on port `8080`
 
 ### Metrics Adapter
 
-The KEDA Metrics Adapter exposes Prometheus metrics which can be scraped on port `9022` (this can be changed by setting the `metrics-port` argument for the Metrics Adapter) at `/metrics`.  The metrics collected in the Metrics Adapter are only active when the HPA is active (> 0 replicas).
+The KEDA Metrics Adapter exposes Prometheus metrics which can be scraped on port `9022` (this can be changed by setting the `metrics-port` argument for the Metrics Adapter) at `/metrics`. The metrics collected in the Metrics Adapter are only active when the HPA is active (> 0 replicas).
 
 The following metrics are being gathered:
 
 - `keda_metrics_adapter_scaler_error_totals` - The total number of errors encountered for all scalers.
 - `keda_metrics_adapter_scaled_object_error_totals`- The number of errors that have occurred for each scaled object.
 - `keda_metrics_adapter_scaler_errors` - The number of errors that have occurred for each scaler.
 - `keda_metrics_adapter_scaler_metrics_value`- The current value for each scaler's metric that would be used by the HPA in computing the target average.
+
+## Premade Grafana dashboard
+
+A premade [Grafana dashboard](https://github.com/kedacore/keda/tree/main/config/grafana/keda-dashboard.json) is available to visualize metrics exposed by the KEDA Metrics Adapter.
+
+![KEDA Grafana dashboard](/img/grafana-dashboard.png)
+
+The dashboard has two sections:
+
+- Visualization of KEDA's metric server
+- Visualization of the scale target and its changes in replicas scaled by KEDA
+
+On top, the dashboard supports the following variables:
+
+- datasource
+- namespace
+- scaledObject
+- scaler
+- metric