CKA Workload Management and Scheduling Flashcards

What is the purpose of a taint applied to a Kubernetes node?

Answer: To repel Pods from being scheduled on that node unless they have a matching toleration

A taint marks a node so that the scheduler will not place Pods on it unless a Pod explicitly tolerates that taint.

Which taint effect prevents new Pods from being scheduled on a node but allows existing Pods to continue running?

Answer: NoSchedule

The NoSchedule effect stops the scheduler from placing new Pods on the tainted node, but does not evict Pods that are already running there.

What does a Pod's 'nodeSelector' field do in Kubernetes scheduling?

Answer: Constrains the Pod to run only on nodes with matching key-value labels

nodeSelector is the simplest node selection constraint; it restricts Pod scheduling to nodes whose labels include all specified key-value pairs.

What is the difference between 'requiredDuringSchedulingIgnoredDuringExecution' and 'preferredDuringSchedulingIgnoredDuringExecution' in node affinity?

Answer: Required is a hard constraint the scheduler must satisfy; preferred is a soft hint the scheduler tries but may ignore

Required affinity rules are mandatory — the Pod will not be scheduled if no node matches — while preferred rules express a preference the scheduler tries to honor but can skip.

What does the kubectl command 'kubectl cordon ' do?

Answer: Marks the node as unschedulable so no new Pods are placed on it

kubectl cordon marks a node as unschedulable, preventing new Pods from being scheduled on it, but does not evict existing Pods.

What is the purpose of Pod affinity rules in Kubernetes scheduling?

Answer: To attract or repel Pods from being co-located with other Pods matching certain labels

Pod affinity and anti-affinity rules let you control whether Pods should be scheduled near (or away from) other Pods that match a given label selector.