Question 340
At Northstar finance, in an isolated training cluster during a scheduled maintenance rehearsal: Deployment invoice-api in namespace ledger was just updated with a faulty Pod template and must return to its prior revision. Work only within the stated target and verify before declaring success. Which operational control most directly prevents this failure or configuration drift?
Explanation
Correct Answer
Retain meaningful revisions and perform health checks after every rollback. This reduces recurrence of the specific operational failure. It reinforces the action: Run kubectl -n ledger rollout undo deployment/invoice-api after checking rollout history. The relevant mechanism is: A Deployment tracks ReplicaSet revisions and rollout undo restores a recorded earlier Pod template.
Incorrect Answers
That safeguard is relevant to: Node selectors constrain scheduling to nodes whose labels match all specified key/value pairs; patching the Pod template triggers a rollout. The current failure instead follows from: A Deployment tracks ReplicaSet revisions and rollout undo restores a recorded earlier Pod template. Its prevention measure is “Retain meaningful revisions and perform health checks after every rollback”.
This routine guards against another mechanism: HPA evaluates metrics relative to Pod resource requests; missing metrics or requests can leave desired replicas unknown. The recurring exposure in the current case is: A Deployment tracks ReplicaSet revisions and rollout undo restores a recorded earlier Pod template. The matching preventive check is “Retain meaningful revisions and perform health checks after every rollback”.
The suggested review tracks a different technical risk: Rollout restart annotates the Pod template so the Deployment controller replaces Pods according to its rollout strategy. Here the sustained control must address: A Deployment tracks ReplicaSet revisions and rollout undo restores a recorded earlier Pod template. Choose “Retain meaningful revisions and perform health checks after every rollback”.