Which service type creates a DNS CNAME-like alias of another domain?

Which service type creates a DNS CNAME-like alias of another domain?

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

Answer: (A)

ExternalName is the service type that creates a DNS alias to an external domain. When you configure a service with an externalName, Kubernetes does not allocate a cluster IP or endpoints. Instead, the service’s DNS name resolves to the provided external domain, behaving like a CNAME. This lets pods access the external service using the Kubernetes service name, while traffic is directed to the outside domain. Other service types—ClusterIP assigns an internal cluster IP, NodePort exposes a port on each node, and LoadBalancer provisions an external load balancer—do not create this DNS alias behavior.

ExternalName is the service type that creates a DNS alias to an external domain. When you configure a service with an externalName, Kubernetes does not allocate a cluster IP or endpoints. Instead, the service’s DNS name resolves to the provided external domain, behaving like a CNAME. This lets pods access the external service using the Kubernetes service name, while traffic is directed to the outside domain. Other service types—ClusterIP assigns an internal cluster IP, NodePort exposes a port on each node, and LoadBalancer provisions an external load balancer—do not create this DNS alias behavior.