Certified Kubernetes Application Developer (CKAD) Practice Test

What is the effect of associating a pod with a headless service?

1. It creates a static IP for the pod.

2. It helps in scaling the pod horizontally.

3. It assigns a DNS record for each pod instance.

4. It provides rolling updates for the service.

The correct answer is: It assigns a DNS record for each pod instance.

Associating a pod with a headless service results in the assignment of a DNS record for each individual pod instance. In a typical Kubernetes service, a single IP address is assigned to the service, which routes traffic to the associated pods. However, a headless service, which is created by omitting the clusterIP field or setting it to "None," does not allocate a single IP. Instead, it enables DNS records to be created for each individual pod backing that service. This allows clients to resolve the DNS name of the headless service to the set of pod IPs, providing a way to directly connect to each pod. This is especially useful for applications that require knowledge of the individual pod instances, such as when using stateful applications, service discovery, or in situations where specific connections to pod instances are necessary for scaling or redundancy. The other options focus on aspects that do not directly relate to the core functionality of a headless service. Therefore, the correct answer reflects the unique provision of DNS resolution for individual pods within a headless service setup, enabling a more detailed and granular approach to service interaction within Kubernetes.