This commit wires together the graceful delete option for pods
on the Kubelet. When a pod is deleted on the API server, a
grace period is calculated that is based on the
Pod.Spec.TerminationGracePeriodInSeconds, the user's provided grace
period, or a default. The grace period can only shrink once set.
The value provided by the user (or the default) is set onto metadata
as DeletionGracePeriod.
When the Kubelet sees a pod with DeletionTimestamp set, it uses the
value of ObjectMeta.GracePeriodSeconds as the grace period
sent to Docker. When updating status, if the pod has DeletionTimestamp
set and all containers are terminated, the Kubelet will update the
status one last time and then invoke Delete(pod, grace: 0) to
clean up the pod immediately.
Per-pod workers have sufficient knowledge to determine whether a pod has
exceeded the active deadline, and they set the status at the end of each sync.
Move the active deadline check to generatePodStatus so that per pod workers
can update the pod status directly. This eliminates the possibility of a race
condition where both SyncPods and the pod worker are updating the status, which
could lead to temporary erratic pod status behavior (pod phase: failed ->
running -> failed).
Maxwell Forbes