In StatefulSets, which service type is used to enable DNS-based addressing without a cluster IP?

In StatefulSets, which service type is used to enable DNS-based addressing without a cluster IP?

• A. A standard cluster IP service
• B. A service with a dedicated external IP
• C. A service that routes traffic via external name
• D. A headless service that enables DNS without a cluster IP

Answer: (D)

In StatefulSets, you want each pod to have a stable network identity and be addressable directly by DNS without routing through a single cluster IP. This is achieved with a headless service, which has no cluster IP (clusterIP: None). With a headless service, DNS resolves to the individual pods, giving each ordinal pod a stable hostname like <statefulset-name>-<ordinal>.<service-name>.<namespace>.svc.cluster.local. This enables DNS-based addressing exactly for the per-pod identities that StatefulSets rely on. Other service types always allocate a cluster IP and present a single virtual IP, which doesn’t provide per-pod DNS records required for direct pod addressing. ExternalName maps to external addresses and isn’t used for internal DNS resolution of pods.

In StatefulSets, you want each pod to have a stable network identity and be addressable directly by DNS without routing through a single cluster IP. This is achieved with a headless service, which has no cluster IP (clusterIP: None). With a headless service, DNS resolves to the individual pods, giving each ordinal pod a stable hostname like -...svc.cluster.local. This enables DNS-based addressing exactly for the per-pod identities that StatefulSets rely on.

Other service types always allocate a cluster IP and present a single virtual IP, which doesn’t provide per-pod DNS records required for direct pod addressing. ExternalName maps to external addresses and isn’t used for internal DNS resolution of pods.