Kubernetes Container Orchestration Scheduling and Scaling 3

Question 1

Which scheduler plugin phase is responsible for filtering out nodes that cannot run a pod?

Accepted Answer

Filter

Answer

The Filter phase runs predicates (e.g., NodeResourcesFit, NodeAffinity) to eliminate nodes that are ineligible for the pod.

Question 2

You need pods of a Deployment to spread evenly across availability zones. Which spec field achieves this without writing custom affinity rules?

Accepted Answer

spec.template.spec.topologySpreadConstraints

Answer

topologySpreadConstraints lets you declare a maxSkew and topology key (e.g., topology.kubernetes.io/zone) to spread pods evenly.

Question 3

What happens to a pod with `priorityClassName: low-priority` when a high-priority pod cannot be scheduled due to insufficient resources?

Accepted Answer

The low-priority pod is evicted to free resources for the high-priority pod

Answer

The scheduler's preemption logic evicts lower-priority pods to make room for higher-priority pods that cannot otherwise be scheduled.

Question 4

Which command shows the reason a pod is stuck in Pending state due to scheduling failure?

Accepted Answer

kubectl describe pod <pod>

Answer

kubectl describe pod shows the Events section with FailedScheduling messages that explain why no node was selected.

Question 5

A KEDA ScaledObject targets a Kafka consumer group. What does KEDA use to determine the desired replica count?

Accepted Answer

Consumer group lag (number of unprocessed messages)

Answer

KEDA scales based on event source metrics like consumer group lag, allowing it to scale to zero when there are no messages.

Kubernetes Container Orchestration Practice Test