KCNA Cloud Native Observability Practice Question
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?
⚠ Common exam trap
Watch out — 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.
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
✓
Query Prometheus for kubelet metrics on probe successes and failures
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.
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.
- ✗
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.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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