PriorityClasses and Preemption — Who Gets Evicted When the Cluster Is Full

Twice on Day 21 the FailedScheduling event ended with a preemption: clause — the scheduler checking whether evicting someone else would make room, and concluding it would not help. Day 22 makes it help. Create PriorityClass tiers, pack the cluster full of low-priority filler Pods, then submit one critical Pod and watch the scheduler kill a filler mid-flight to seat it — nominatedNodeName, Preempted events, graceful termination and all. Plus why kube-proxy never loses this fight, the preemptionPolicy: Never queue-jump, and the uncomfortable truth about preemption vs your Day 16 PodDisruptionBudget.