The correct answer is D: On failure. In Kubernetes, restart behavior is controlled by the Pod-level field spec.restartPolicy, with valid values Always, OnFailure, and Never. The option presented here (“On failure”) maps to Kubernetes’ OnFailure policy. This setting determines what the kubelet should do when containers exit:
Always: restart containers whenever they exit (typical for long-running services)
OnFailure: restart containers only if they exit with a non-zero status (common for batch workloads)
Never: do not restart containers (fail and leave it terminated)
So “On failure” is a valid restart policy concept and the only one in the list that matches Kubernetes semantics.
The other options are not Kubernetes restart policies. “On login,” “On update,” and “On start” are not recognized values and don’t align with how Kubernetes models container lifecycle. Kubernetes is declarative and event-driven: it reacts to container exit codes and controller intent, not user “logins.”
Operationally, choosing the right restart policy is important. For example, Jobs typically use restartPolicy: OnFailure or Never because the goal is completion, not continuous uptime. Deployments usually imply “Always” because the workload should keep serving traffic, and a crashed container should be restarted. Also note that controllers interact with restarts: a Deployment may recreate Pods if they fail readiness, while a Job counts completions and failures based on Pod termination behavior.
Therefore, among the options, the only valid (Kubernetes-aligned) restart policy is D.
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