Which service type makes services technically available outside the cluster if node IPs are externally accessible?

Which service type makes services technically available outside the cluster if node IPs are externally accessible?

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

Answer: (D)

Exposing the service on a fixed port on every node allows external clients to reach the application as long as the node IPs are reachable. This is what NodePort does: it allocates a port (in the 30000–32767 range by default) on every node, and traffic to any node’s IP at that port is forwarded to the service and then to the backing pods. You can access it with http://<node-ip>:<node-port>. ExternalName would simply map the service to an external DNS name, not provide a port on the cluster nodes. ClusterIP keeps the service accessible only within the cluster. LoadBalancer creates an external load balancer via the cloud provider, which is another way to expose services externally but depends on cloud integration. NodePort is the mechanism that makes the service technically available outside the cluster using the node IPs if they’re reachable.

Exposing the service on a fixed port on every node allows external clients to reach the application as long as the node IPs are reachable. This is what NodePort does: it allocates a port (in the 30000–32767 range by default) on every node, and traffic to any node’s IP at that port is forwarded to the service and then to the backing pods. You can access it with http://:.

ExternalName would simply map the service to an external DNS name, not provide a port on the cluster nodes. ClusterIP keeps the service accessible only within the cluster. LoadBalancer creates an external load balancer via the cloud provider, which is another way to expose services externally but depends on cloud integration. NodePort is the mechanism that makes the service technically available outside the cluster using the node IPs if they’re reachable.