Question 320
At Horizon observability, in a disposable simulated environment during a monitored release window: The Deployment metrics-api in observability needs its named container app updated to approved image registry.example.test/metrics-api:v3. 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
Pin reviewed image tags or digests and retain rollout history for recovery. This reduces recurrence of the specific operational failure. It reinforces the action: Run kubectl -n observability set image deployment/metrics-api app=registry.example.test/metrics-api:v3. The relevant mechanism is: Updating a Deployment Pod template triggers a controlled rollout; restarting Pods alone will not change the image reference.
Incorrect Answers
This routine guards against another mechanism: Node selectors constrain scheduling to nodes whose labels match all specified key/value pairs; patching the Pod template triggers a rollout. The recurring exposure in the current case is: Updating a Deployment Pod template triggers a controlled rollout; restarting Pods alone will not change the image reference. The matching preventive check is “Pin reviewed image tags or digests and retain rollout history for recovery”.
The suggested review tracks a different technical risk: HPA evaluates metrics relative to Pod resource requests; missing metrics or requests can leave desired replicas unknown. Here the sustained control must address: Updating a Deployment Pod template triggers a controlled rollout; restarting Pods alone will not change the image reference. Choose “Pin reviewed image tags or digests and retain rollout history for recovery”.
This routine guards against another mechanism: Deployment rolling-update parameters govern how many old Pods may be unavailable and extra Pods may be created during replacement. The recurring exposure in the current case is: Updating a Deployment Pod template triggers a controlled rollout; restarting Pods alone will not change the image reference. The matching preventive check is “Pin reviewed image tags or digests and retain rollout history for recovery”.