Which service type acts as a DNS alias to another domain?

Which service type acts as a DNS alias to another domain?

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

Answer: (C)

ExternalName is the service type that acts as a DNS alias to another domain. When you create a service with type ExternalName and set spec.externalName to an external hostname, Kubernetes does not allocate a cluster IP or create endpoints. Instead, the service’s DNS name resolves directly to that external domain, so pods using the service name reach the external resource as if it were a DNS alias inside the cluster. This is useful for referencing existing external services from Kubernetes without adding a proxy. Other service types—ClusterIP, NodePort, and LoadBalancer—expose services inside or at the edge of the cluster and do not provide a DNS alias to a different domain.

ExternalName is the service type that acts as a DNS alias to another domain. When you create a service with type ExternalName and set spec.externalName to an external hostname, Kubernetes does not allocate a cluster IP or create endpoints. Instead, the service’s DNS name resolves directly to that external domain, so pods using the service name reach the external resource as if it were a DNS alias inside the cluster. This is useful for referencing existing external services from Kubernetes without adding a proxy. Other service types—ClusterIP, NodePort, and LoadBalancer—expose services inside or at the edge of the cluster and do not provide a DNS alias to a different domain.