Quality of Service classes (Guaranteed, Burstable, BestEffort) in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Kubernetes QoS Classes

Which Quality of Service (QoS) class in Kubernetes guarantees that a pod will never be evicted due to resource contention?

A BestEffort

B Burstable

C Guaranteed

D None of the above

💡 Hint

Think about which class requires both requests and limits to be set equally.

The Guaranteed QoS class requires that every container in the pod has memory and CPU requests and limits set to the same values. This ensures the pod is the last to be evicted under resource pressure.

💻 Command Output

intermediate

Identifying QoS Class from Pod Description

Given the following pod YAML snippet, what is the QoS class assigned to this pod?

apiVersion: v1
kind: Pod
metadata:
  name: example-pod
spec:
  containers:
  - name: app
    image: nginx
    resources:
      requests:
        memory: "100Mi"
        cpu: "100m"
      limits:
        memory: "200Mi"
        cpu: "200m"

A Burstable

B Guaranteed

C BestEffort

D No QoS class assigned

💡 Hint

Check if requests and limits are equal for all resources.

The pod has resource requests and limits set, but they are not equal. This makes the pod Burstable. Guaranteed requires requests and limits to be equal.

❓ Configuration

advanced

Configuring a Pod for BestEffort QoS Class

Which pod resource configuration will result in the pod being assigned the BestEffort QoS class?

A Containers have no resource requests or limits defined

B Containers have resource requests but no limits

C Containers have resource limits but no requests

D Containers have equal resource requests and limits

💡 Hint

BestEffort pods do not reserve any resources.

BestEffort QoS class is assigned when no resource requests or limits are set for any container in the pod.

❓ Troubleshoot

advanced

Pod Eviction Behavior Under Resource Pressure

You notice that a pod with resource requests and limits set differently is evicted during node resource pressure. What is the most likely QoS class of this pod?

A BestEffort

B Guaranteed

C No QoS class

D Burstable

💡 Hint

Recall eviction priority order based on QoS classes.

Burstable pods have resource requests and limits set but not equal, so they have lower eviction priority than Guaranteed but higher than BestEffort.

🔀 Workflow

expert

Determining QoS Class Using kubectl

You want to check the QoS class of a running pod named web-server. Which kubectl command will show this information directly?

A kubectl describe pod web-server | grep QoS

B kubectl get pod web-server -o jsonpath='{.status.qosClass}'

C kubectl get pod web-server --show-labels

D kubectl logs web-server | grep QoS

💡 Hint

Look for a command that extracts the QoS class from pod status.

The jsonpath option extracts the QoS class directly from the pod's status field. The other commands either do not show QoS or show unrelated information.