KCNA Container Orchestration Practice Question
Your application consists of a frontend and a backend. The frontend needs to communicate with the backend using a stable DNS name. The backend is deployed as a Deployment with 3 replicas. Which Kubernetes resource should you create to provide a stable DNS name for the backend?
⚠ Common exam trap
CNCF often tests the misconception that a Service of type NodePort is required for any DNS-based communication, but the trap here is that ClusterIP is the correct choice for internal cluster DNS stability, while NodePort is only needed for external access.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Service of type ClusterIP
A Service of type ClusterIP provides a stable virtual IP and DNS name (e.g., my-service.namespace.svc.cluster.local) that load-balances traffic across the backend Pods. This is the correct resource because the frontend only needs a stable DNS name for internal cluster communication, and ClusterIP is the default Service type that fulfills this requirement without exposing the backend externally.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
EndpointSlice
Why it's wrong here
EndpointSlices track pod IP addresses for a Service but provide no DNS name themselves; clients cannot resolve them. It is tempting because EndpointSlices sit behind service discovery, and would be correct when manually managing endpoints for a headless Service or external backend without selectors.
- ✗
Service of type NodePort
Why it's wrong here
A NodePort Service does supply a stable DNS name, but it also exposes the backend on every node's IP at a static port, which the frontend does not require. It is tempting because it provides both DNS and external reachability, and would be correct if clients outside the cluster needed to reach the backend directly.
- ✗
Ingress
Why it's wrong here
Ingress routes external HTTP traffic to Services and depends on one already existing; it creates no DNS name for the backend pods. It is tempting because it handles service-to-service routing, and would be correct when exposing the frontend externally with host- or path-based rules.
- ✓
Service of type ClusterIP
Why this is correct
A ClusterIP Service assigns a stable virtual IP and DNS name, load-balancing across the Deployment's three pod replicas. Pod IPs change on restart, so the Service abstraction provides the consistent in-cluster DNS name the frontend requires.
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Same concept, more angles
1 more way this is tested on KCNA
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You have a microservices application deployed as a set of Pods in a Kubernetes cluster. You need to ensure that Pods can discover each other using stable DNS names. Which Kubernetes resource should you create?
medium- A.ConfigMap
- B.Ingress
- ✓ C.Service
- D.Deployment
Why C: A Service of type ClusterIP (the default) provides a stable virtual IP and DNS name (e.g., my-service.namespace.svc.cluster.local) that resolves to the Pods selected by its label selector. This allows Pods to discover each other using consistent DNS names, regardless of Pod IP changes due to scaling or restarts. The kube-dns or CoreDNS addon automatically creates DNS records for Services, enabling service discovery within the cluster.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This KCNA practice question is part of Courseiva's free CNCF certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the KCNA exam.