* feature(sscheduling_queue): track events per Pods
* fix typos
* record events in one slice and make each in-flight Pod to refer it
* fix: use Pop() in test before AddUnschedulableIfNotPresent to register in-flight Pods
* eliminate MakeNextPodFuncs
* call Done inside the scheduling queue
* fix comment
* implement done() not to require lock in it
* fix UTs
* improve the receivedEvents implementation based on suggestions
* call DonePod when we don't call AddUnschedulableIfNotPresent
* fix UT
* use queuehint to filter out events for in-flight Pods
* fix based on suggestion from aldo
* fix based on suggestion from Wei
* rename lastEventBefore → previousEvent
* fix based on suggestion
* address comments from aldo
* fix based on the suggestion from Abdullah
* gate in-flight Pods logic by the SchedulingQueueHints feature gate
PVCs using the ReadWriteOncePod access mode can only be referenced by a
single pod. When a pod is scheduled that uses a ReadWriteOncePod PVC,
return "Unschedulable" if the PVC is already in-use in the cluster.
To support preemption, the "VolumeRestrictions" scheduler plugin
computes cycle state during the PreFilter phase. This cycle state
contains the number of references to the ReadWriteOncePod PVCs used by
the pod-to-be-scheduled.
During scheduler simulation (AddPod and RemovePod), we add and remove
reference counts from the cycle state if they use any of these
ReadWriteOncePod PVCs.
In the Filter phase, the scheduler checks if there are any PVC reference
conflicts, and returns "Unschedulable" if there is a conflict.
This is a required feature for the ReadWriteOncePod beta. See for more context:
https://github.com/kubernetes/enhancements/tree/master/keps/sig-storage/2485-read-write-once-pod-pv-access-mode#beta
- PreemptionByKubeScheduler (Pod preempted by kube-scheduler)
- DeletionByTaintManager (Pod deleted by taint manager due to NoExecute taint)
- EvictionByEvictionAPI (Pod evicted by Eviction API)
- DeletionByPodGC (an orphaned Pod deleted by PodGC)PreemptedByScheduler (Pod preempted by kube-scheduler)
