Which Kubernetes service is only accessible within the cluster?

Which Kubernetes service is only accessible within the cluster?

• A. Ingress
• B. ExternalName
• C. NodePort
• D. ClusterIP

Answer: (D)

ClusterIP is the internal-only service in Kubernetes. It assigns a virtual IP that is reachable only from inside the cluster, so pods can communicate with the service via its DNS name or cluster IP. This makes it ideal for internal communication between microservices. It cannot be reached from outside the cluster without extra wiring, such as a NodePort or LoadBalancer, or via an Ingress that routes external traffic to an internal service. ExternalName points to an external DNS name, not a cluster IP. Ingress is a separate resource used to expose external HTTP(S) traffic to services inside the cluster, with the actual service typically being a ClusterIP inside.

ClusterIP is the internal-only service in Kubernetes. It assigns a virtual IP that is reachable only from inside the cluster, so pods can communicate with the service via its DNS name or cluster IP. This makes it ideal for internal communication between microservices. It cannot be reached from outside the cluster without extra wiring, such as a NodePort or LoadBalancer, or via an Ingress that routes external traffic to an internal service. ExternalName points to an external DNS name, not a cluster IP. Ingress is a separate resource used to expose external HTTP(S) traffic to services inside the cluster, with the actual service typically being a ClusterIP inside.