KCNA Kubernetes Fundamentals Practice Question
A Service of type ClusterIP is not resolving DNS names for pods. The pods are running and can communicate with each other via IP addresses. Which component should be checked first?
⚠ Common exam trap
A common misconception is that DNS failures are caused by kube-proxy or network proxy issues, when in fact DNS resolution is a separate layer handled by CoreDNS, and candidates should first verify the DNS pods themselves.
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
✓
CoreDNS pods in the kube-system namespace
DNS name resolution for Services in Kubernetes is handled by CoreDNS, which runs as pods in the kube-system namespace. When a ClusterIP Service fails to resolve DNS names but pods can communicate via IP addresses, the issue is almost certainly with the DNS resolver itself, not with network connectivity or Service endpoints. CoreDNS must be checked first to ensure it is running, has correct configuration, and can query the Kubernetes API for Service records.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The kubelet on the node where the pod is running
Why it's wrong here
kubelet ensures containers are running, but does not handle DNS resolution.
- ✗
The Service's endpoint slices
Why it's wrong here
Endpoint slices contain the list of pod IPs but do not handle DNS.
- ✗
kube-proxy on the nodes
Why it's wrong here
kube-proxy handles network rules for service IPs, not DNS.
- ✓
CoreDNS pods in the kube-system namespace
Why this is correct
CoreDNS provides DNS resolution for cluster services.
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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.