Quality of Service classes (Guaranteed, Burstable, BestEffort) in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are the three Quality of Service (QoS) classes in Kubernetes?

The three QoS classes are Guaranteed, Burstable, and BestEffort. They define how Kubernetes manages pod resources under pressure.

intermediate

What conditions must a pod meet to be classified as Guaranteed QoS in Kubernetes?

A pod is Guaranteed if every container has memory and CPU requests equal to their limits. This means the pod gets the highest priority for resources.

intermediate

Describe the <strong>Burstable</strong> QoS class in Kubernetes.

A pod is Burstable if it has resource requests and limits set, but requests are less than limits for at least one resource. It can use extra resources when available but may be throttled under pressure.

beginner

What happens to a BestEffort pod during resource contention in Kubernetes?

BestEffort pods have no resource requests or limits set. They get the lowest priority and are the first to be evicted when the node runs out of resources.

intermediate

How does Kubernetes determine the QoS class of a pod?

Kubernetes checks the resource requests and limits of all containers in the pod. Based on their presence and equality, it assigns the pod to Guaranteed, Burstable, or BestEffort.

Which QoS class in Kubernetes guarantees the highest priority for resource allocation?

A None

B Burstable

C BestEffort

D Guaranteed

The Guaranteed class ensures pods have equal resource requests and limits, giving them the highest priority.

A pod with no resource requests or limits set falls under which QoS class?

A BestEffort

B Guaranteed

C Burstable

D Critical

Pods without any resource requests or limits are classified as BestEffort.

If a pod has CPU requests less than CPU limits, what QoS class does it belong to?

A Burstable

B BestEffort

C Guaranteed

D None

When requests are less than limits, the pod is Burstable.

Which QoS class pods are evicted first during node resource pressure?

A Guaranteed

B BestEffort

C All equally

D Burstable

BestEffort pods have the lowest priority and are evicted first.

What must be true for a pod to be classified as Guaranteed?

A Requests less than limits for some containers

B No resource requests or limits

C Requests equal limits for all containers

D Only CPU requests set

Guaranteed requires requests and limits to be equal for every container.

Explain the differences between Guaranteed, Burstable, and BestEffort QoS classes in Kubernetes.

Think about resource requests and limits and how Kubernetes uses them to prioritize pods.

Describe how Kubernetes uses QoS classes to manage pod eviction during resource shortages.

Consider which pods have resource guarantees and which do not.