We chose to use podFullName (name_namespace) as key in the status manager
because mirror pod and static pod share the same status. This is no longer
needed because we do not store statuses for static pods anymore (we only
store statuses for their mirror pods). Also, reviously, a few fixes were
merged to ensure statuses are cleaned up so that a new pod with the same
name would not resuse an old status.
This change cleans up the code by using UID as key so that the code would
become less brittle.
The sync loop should check for terminated pods that are no longer
running and clear them. The status loop should never write status
if the pod UID changes. Mirror pods should be deleted immediately
rather than gracefully.
Avoid TTL by deleting pods immediately when they aren't
scheduled, and letting the Kubelet delete them otherwise.
Ensure the Kubelet uses pod.Spec.TerminationGracePeriodSeconds
when no pod.DeletionGracePeriodSeconds is available.
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).
Yu-Ju Hong