Storage classes for dynamic provisioning in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the main purpose of a StorageClass in Kubernetes?

Choose the best description of what a StorageClass does in Kubernetes dynamic provisioning.

A Schedules pods to nodes based on resource availability.

B Defines how to dynamically create persistent storage volumes with specific parameters.

C Manages user access control for Kubernetes clusters.

D Specifies the network policies for pod communication.

💡 Hint

Think about what StorageClass controls related to storage.

A StorageClass tells Kubernetes how to create storage volumes dynamically with certain settings like type and performance.

💻 Command Output

intermediate

Output of kubectl get storageclass command

What output will you see after running kubectl get storageclass if there is one default StorageClass named fast-storage?

Kubernetes

kubectl get storageclass

A

NAME           PROVISIONER                RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
slow-storage   kubernetes.io/gce-pd       Delete         Immediate             true                  5d

B

NAME           PROVISIONER                RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
fast-storage   kubernetes.io/aws-ebs      Retain         Immediate             false                 10d

C

NAME           PROVISIONER                RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
fast-storage   kubernetes.io/aws-ebs      Delete         WaitForFirstConsumer   true                  10d
(default)

D No resources found in default namespace.

💡 Hint

Look for the default StorageClass and its typical fields.

The output lists StorageClasses with their provisioner, reclaim policy, binding mode, expansion allowance, age, and default marker.

❓ Configuration

advanced

Identify the error in this StorageClass YAML

Which option correctly identifies the error in this StorageClass YAML snippet?

Kubernetes

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast-storage
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
reclaimPolicy: Delete
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: yes

A The provisioner 'kubernetes.io/aws-ebs' is invalid and should be 'aws-ebs-provisioner'.

B The volumeBindingMode 'WaitForFirstConsumer' is deprecated and should be 'Immediate'.

C The reclaimPolicy field should be under parameters, not at root level.

D The value 'yes' for allowVolumeExpansion should be a boolean true, not a string.

💡 Hint

Check the data types for boolean fields in YAML.

In YAML, boolean fields like allowVolumeExpansion must be true or false without quotes. 'yes' as a string is invalid.

❓ Troubleshoot

advanced

Why does PVC remain Pending with dynamic provisioning?

A PersistentVolumeClaim (PVC) stays in Pending state even though a StorageClass is specified. What is the most likely cause?

A The StorageClass provisioner is not installed or available in the cluster.

B The PVC size is larger than the node's CPU capacity.

C The PVC does not specify a storageClassName field.

D The pod using the PVC is not scheduled yet.

💡 Hint

Think about what happens when Kubernetes tries to create a volume dynamically.

If the provisioner for the StorageClass is missing, Kubernetes cannot create the volume, so the PVC stays Pending.

🔀 Workflow

expert

Correct order to create and use dynamic storage in Kubernetes

Put these steps in the correct order to dynamically provision storage and use it in a pod.

A 1,2,4,3

B 2,1,4,3

C 1,4,2,3

D 2,4,1,3

💡 Hint

Think about what must exist before requesting storage and before using it in a pod.

First create StorageClass, then PVC referencing it, then Kubernetes provisions PV, then pod uses PVC.