This KCNA practice question tests your understanding of kubernetes fundamentals. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A user reports that a web application is not accessible via its Service. The Service is of type ClusterIP. Which TWO steps should be taken to troubleshoot?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Verify that the kube-proxy is running on the node
Option A is correct because kube-proxy is the component responsible for implementing the ClusterIP Service abstraction by managing iptables or IPVS rules on each node. If kube-proxy is not running, traffic destined for the Service's ClusterIP will not be forwarded to the backend pods, making the Service unreachable from within the cluster.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Verify that the kube-proxy is running on the node
Why this is correct
kube-proxy is responsible for implementing the Service abstraction via iptables or IPVS.
Related concept
Read the scenario before looking for a memorised answer.
✗
Check that the container runtime is working
Why it's wrong here
Container runtime issues affect Pods, but the Service connectivity problem is likely at the network layer.
✗
Check the kube-apiserver status
Why it's wrong here
The API server is for managing the cluster state, not for forwarding traffic to Services.
✓
Check if the Service has any endpoints using 'kubectl get endpoints'
Why this is correct
Endpoints show the Pods that the Service routes to.
Related concept
Read the scenario before looking for a memorised answer.
✗
Restart all nodes in the cluster
Why it's wrong here
This is a drastic measure and not an appropriate first troubleshooting step.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume a Service is always reachable if the pods are running, forgetting that kube-proxy must be healthy and that the Service must have endpoints for traffic to be forwarded.
Detailed technical explanation
How to think about this question
Under the hood, kube-proxy watches the Kubernetes API for Service and EndpointSlice changes and updates iptables NAT rules (or IPVS virtual servers) to redirect traffic from the Service ClusterIP to the pod IPs. A common subtle issue is that if the Service has no endpoints (e.g., due to a mismatched label selector), kube-proxy will not install any rules, causing traffic to be dropped silently. In real-world scenarios, checking `kubectl get endpoints` is the fastest way to confirm whether the Service is backed by ready pods.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the KCNA exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this KCNA question in full detail.
Kubernetes Fundamentals — This question tests Kubernetes Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Verify that the kube-proxy is running on the node — Option A is correct because kube-proxy is the component responsible for implementing the ClusterIP Service abstraction by managing iptables or IPVS rules on each node. If kube-proxy is not running, traffic destined for the Service's ClusterIP will not be forwarded to the backend pods, making the Service unreachable from within the cluster.
What should I do if I get this KCNA question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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