Which command creates a service of type ExternalName mapping to the host customerdb.oracle.com?

• A. oc create service externalname customerdb --external-name customerdb.oracle.com
• B. oc create service externalname customerdb --external-name customerdb.oracle
• C. oc create service externalname customerdb --external-name customerdb.oracle.com
• D. oc create service externalname externalname customerdb --external-name customerdb.oracle.com

Answer: (C)

ExternalName services act as a DNS alias inside the cluster, pointing a service name to an external host. To create such a service, you specify the service name you want inside the cluster and map it to the external DNS name with the --external-name flag. Here, you want a service named customerdb that resolves to customerdb.oracle.com, so the correct command is: oc create service externalname customerdb --external-name customerdb.oracle.com. This creates a DNS entry so pods querying for customerdb will reach the external host at customerdb.oracle.com. The other options would either name the service incorrectly or supply an invalid external name (like omitting .com) or misuse the command structure.