improvement psa document

Signed-off-by: Ugur <[email protected]>

Author: ugur99

content/en/docs/concepts/security/pod-security-admission.md

@@ -125,6 +125,14 @@ current policy level:
 - Valid updates to `.spec.activeDeadlineSeconds`
 - Valid updates to `.spec.tolerations`
 
+## Metrics
+You can look at the following Prometheus metrics exposed by kube-apiserver.
+
+- `pod_security_errors_total`: metric contains the number of errors preventing normal evaluation. Non-fatal errors may result in the latest restricted profile being used for evaluation.
+- `pod_security_evaluations_total`: metric contains the number of policy evaluations that occurred, not counting ignored or exempt requests.
+  during exporting.
+- `pod_security_exemptions_total`: metric contains the number of exempt requests, not counting ignored or out of scope requests.
+
 ## {{% heading "whatsnext" %}}
 
 - [Pod Security Standards](/docs/concepts/security/pod-security-standards)