Calculate expected duration of a helm rollback to a previous release revision.
`helm rollback` reverts a release to a previously stored revision: Helm looks up that revision's manifest from its storage backend, re-applies it as a new revision, and Kubernetes then has to terminate current pods and bring up pods matching the reverted spec. Pod restart time — driven by image pulls, container startup, and readiness probes — is almost always the dominant cost, dwarfing the near-instant revision lookup and apply steps.
totalTime = revisionLookup + manifestApply + podRestart
Usually yes for the render/diff overhead, since the manifest is already stored, but pod restart time is comparable to an upgrade because Kubernetes still has to reschedule and re-ready the pods for the reverted spec.
By default Helm 3 does not run most hooks on rollback unless explicitly configured; the `--no-hooks` behavior varies by hook type, so pre/post-rollback hooks (if defined) can add to the duration.
Keep readiness probes tight but accurate, pre-pull images used by recent revisions onto nodes, and avoid rollback targets that require large stateful pod restarts (e.g. StatefulSets with slow init containers).