This KCNA practice question tests your understanding of cloud native observability. 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 DevOps team notices that a microservice is returning 503 errors intermittently. The service runs in Kubernetes and uses a liveness probe. The team wants to understand the root cause without restarting the pod. Which observability approach should they use first?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Query Prometheus for kubelet metrics on probe successes and failures
Option B is correct because Prometheus can scrape kubelet metrics that expose liveness probe success and failure counts directly, allowing the team to see if the probe is failing without restarting the pod. This approach provides historical data on probe behavior, which is essential for diagnosing intermittent 503 errors that stem from the kubelet restarting the container when the liveness probe fails. Unlike other options, it does not require modifying the application or restarting the pod, and it directly surfaces the root cause if the probe is the issue.
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.
✗
Use kubectl describe pod to check recent events
Why it's wrong here
Events may not capture every probe failure, especially if they are short-lived.
✓
Query Prometheus for kubelet metrics on probe successes and failures
Why this is correct
Metrics like 'probe_success' from kubelet can show probe status over time, helping identify intermittent failures.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increase log verbosity in the application to capture all requests
Why it's wrong here
Logs may not capture probe failures, and increasing verbosity can impact performance.
✗
Enable distributed tracing across the service mesh
Why it's wrong here
Tracing is for request flows, not probe health checks.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume 'kubectl describe pod' (Option A) is sufficient for debugging, but they overlook that its event log is short-lived and may not retain evidence of intermittent failures, whereas Prometheus metrics provide persistent historical data.
Detailed technical explanation
How to think about this question
The kubelet exposes liveness probe metrics at the /metrics endpoint on port 10250, including 'prober_probe_total' with labels for result (success/failure) and probe type. Prometheus scrapes these metrics to provide a time-series view of probe failures, which directly correlate with 503 errors if the kubelet kills the container and Kubernetes routes traffic away from the pod. In a real-world scenario, a misconfigured liveness probe (e.g., a timeout that is too short) can cause intermittent failures that are invisible in application logs but clearly visible in these kubelet metrics.
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.
Cloud Native Observability — This question tests Cloud Native Observability — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Query Prometheus for kubelet metrics on probe successes and failures — Option B is correct because Prometheus can scrape kubelet metrics that expose liveness probe success and failure counts directly, allowing the team to see if the probe is failing without restarting the pod. This approach provides historical data on probe behavior, which is essential for diagnosing intermittent 503 errors that stem from the kubelet restarting the container when the liveness probe fails. Unlike other options, it does not require modifying the application or restarting the pod, and it directly surfaces the root cause if the probe is the issue.
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.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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