An AZ outage takes out 1 of 3 control plane nodes -- what happens?

With 3 control plane nodes and 1 lost, etcd still has a quorum of 2. The cluster continues operating normally -- scheduling, failure recovery, and kubectl commands all work. The remaining 2 control plane nodes handle all API requests. Worker nodes in the affected AZ are lost (nodes become NotReady), their Pods are evicted and rescheduled to healthy nodes in surviving AZs.