Update Blog “exposing-an-application-using-ingress-and-tls-termination-on-kubernetes-in-hpe-greenlake-for-private-cloud-enterprise”

Author: GuopingJia

content/blog/exposing-an-application-using-ingress-and-tls-termination-on-kubernetes-in-hpe-greenlake-for-private-cloud-enterprise.md

@@ -18,4 +18,12 @@ the service type of ClusterIP, runnin on HTTP. Using cert-manager and TLS termin
 
 
 
-## Overview
+### Overview
+
+### Prerequisites
+
+Before starting, make sure you have the following:
+
+* A K8s cluster, being provisioned in HPE GreenLake for Private Cloud Enterprise
+* The kubectl CLI tool, together with the kubeconfig file for accessing the K8s cluster
+* The optional openssl CLI tool, for validating the generated certificates