Question 1190
At Northstar finance, in an isolated training cluster during a scheduled maintenance rehearsal: HorizontalPodAutoscaler invoice-api in ledger shows <unknown> CPU utilization and is not scaling despite a live Deployment. Work only within the stated target and verify before declaring success. Which Kubernetes behavior best explains the required change or diagnosis?
Explanation
Correct Answer
HPA CPU utilization is computed from reported metrics relative to requests; missing metrics or requests can prevent scaling decisions. This explains the stated condition. The corresponding action is: Run kubectl -n ledger describe hpa invoice-api and check the metrics API, CPU requests and target Pod selection. The direct acceptance evidence is: Verify HPA reports a numeric utilization and responds to a controlled load change within configured bounds.
Incorrect Answers
This principle describes a separate cause: A hard nodeSelector must match a Node's actual labels; tolerations or Service routing cannot bypass the unmatched selector. The reported condition is governed by: HPA CPU utilization is computed from reported metrics relative to requests; missing metrics or requests can prevent scaling decisions. The two mechanisms should not be conflated.
A Service may exist without usable backends because labels or Pod readiness do not match expected routing. That explanation applies to a different technical failure. Here the controlling principle is: HPA CPU utilization is computed from reported metrics relative to requests; missing metrics or requests can prevent scaling decisions.
This principle describes a separate cause: Node memory pressure can cause evictions and scheduling instability independent of one container's OOMKilled status. The reported condition is governed by: HPA CPU utilization is computed from reported metrics relative to requests; missing metrics or requests can prevent scaling decisions. The two mechanisms should not be conflated.