Platform & DevOps·Placement, resources and the pod lifecycle
you mark the machine unschedulable and evict everything on it politely, so the upgrade takes an hour instead of a page.
Node drain
Also calleddrain, cordon, node decommission
The two-step process for taking a node out of service: cordon it so nothing new is scheduled there, then evict what is running so it moves elsewhere. It is the routine operation behind every upgrade, resize and spot reclamation, and it is where disruption budgets, grace periods and shutdown handling are all tested at once. A drain that hangs is nearly always a workload with no other place to go or a budget that cannot be met.