Reclaim policies (Retain, Delete) in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Reclaim Policy Effects on Persistent Volumes

In Kubernetes, what happens to a Persistent Volume (PV) when its Persistent Volume Claim (PVC) is deleted and the PV has a Delete reclaim policy?

A The PV is deleted along with its underlying storage resource.

B The PV remains available but is not bound to any PVC.

C The PV is retained and requires manual cleanup of storage.

D The PVC deletion is blocked until the PV is manually deleted.

💡 Hint

Think about what Delete reclaim policy means for storage lifecycle.

With the Delete reclaim policy, deleting the PVC causes Kubernetes to delete the PV and its associated storage resource automatically.

🧠 Conceptual

intermediate

Behavior of Retain Reclaim Policy on Persistent Volumes

What is the behavior of a Persistent Volume (PV) with a Retain reclaim policy after its Persistent Volume Claim (PVC) is deleted?

A The PVC deletion triggers automatic data backup before PV deletion.

B The PV and its data are deleted automatically.

C The PV is immediately available for new PVC binding.

D The PV remains in Released state and data must be manually cleaned.

💡 Hint

Consider what manual steps are needed when reclaim policy is Retain.

With Retain policy, the PV is not deleted after PVC deletion. It stays in Released state and requires manual intervention to clean or reuse.

💻 Command Output

advanced

Output of PV Status After PVC Deletion with Retain Policy

Given a Persistent Volume with reclaim policy set to Retain, what is the status of the PV after its bound Persistent Volume Claim is deleted?

Kubernetes

kubectl get pv my-pv

A STATUS: Released

B STATUS: Available

C STATUS: Bound

D STATUS: Terminating

💡 Hint

Check the PV lifecycle states after PVC deletion with Retain policy.

When PVC is deleted and PV has Retain policy, PV status changes to Released indicating it is no longer bound but data remains.

🔀 Workflow

advanced

Steps to Reuse a PV with Retain Reclaim Policy

Which sequence correctly describes the steps to reuse a Persistent Volume (PV) that has a Retain reclaim policy after its Persistent Volume Claim (PVC) was deleted?

A 3,1,2,4

B 1,2,3,4

C 1,3,2,4

D 2,1,3,4

💡 Hint

Think about cleaning data before making PV available again.

First, data must be cleaned manually. Then PV status is reset to Available. Next, a new PVC is created to bind to the PV.

❓ Troubleshoot

expert

Troubleshooting PV Not Deleting After PVC Removal

A Persistent Volume (PV) with reclaim policy set to Delete is not deleted after its Persistent Volume Claim (PVC) was removed. What is the most likely cause?

A The PV status is still Bound to the deleted PVC.

B The PVC was deleted with --cascade=false flag.

C The underlying storage resource has a finalizer blocking deletion.

D The Kubernetes API server is down, preventing PV deletion.

💡 Hint

Consider what might prevent Kubernetes from deleting storage resources.

Finalizers on the storage resource can block deletion even if reclaim policy is Delete, causing PV to remain.

Practice

1. What does the Retain reclaim policy do in Kubernetes Persistent Volumes?

easy

A. Keeps the volume and data after the PersistentVolumeClaim is deleted for manual cleanup.

B. Automatically deletes the volume and data when the PersistentVolumeClaim is deleted.

C. Prevents any deletion of the PersistentVolumeClaim.

D. Creates a backup of the volume before deletion.

Solution

1. Step 1: Understand reclaim policies

   Reclaim policies define what happens to storage after the claim is deleted.

2. Step 2: Identify Retain behavior

   The Retain policy keeps the volume and data intact for manual intervention.

3. Final Answer:

   Keeps the volume and data after the PersistentVolumeClaim is deleted for manual cleanup. -> Option A

4. Quick Check:

   Retain = Keep data safe [OK]

Hint: Retain means keep data after claim deletion [OK]

Common Mistakes:

• Confusing Retain with automatic deletion
• Thinking Retain backs up data automatically
• Assuming Retain prevents claim deletion

2. Which of the following is the correct YAML snippet to set a PersistentVolume reclaim policy to Delete?

easy

A. persistentVolumeReclaimPolicy: Retain

B. persistentVolumeReclaimPolicy: Delete

C. persistent_volume_reclaim_policy: Delete

D. persistentVolumeReclaimPolicy: delete

Solution

1. Step 1: Check correct YAML key and value

   The key is persistentVolumeReclaimPolicy, and value is case-sensitive.

2. Step 2: Identify correct value for Delete

   The value must be exactly Delete with capital D.

3. Final Answer:

   persistentVolumeReclaimPolicy: Delete -> Option B

4. Quick Check:

   Correct key and capitalized value = A [OK]

Hint: Use exact key 'persistentVolumeReclaimPolicy' and capitalized 'Delete' [OK]

Common Mistakes:

• Using lowercase 'delete' instead of 'Delete'
• Using underscore instead of camelCase key
• Mixing Retain and Delete values

3. Given this PersistentVolume YAML snippet:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-example
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  hostPath:
    path: /data/pv-example

What happens to the volume when the PersistentVolumeClaim using this PV is deleted?

medium

A. The volume and data are deleted automatically.

B. The volume is unbound but data is deleted.

C. The volume is retained and data remains for manual cleanup.

D. The volume is backed up before deletion.

Solution

1. Step 1: Identify reclaim policy in YAML

   The reclaim policy is set as Retain in persistentVolumeReclaimPolicy.

2. Step 2: Understand Retain effect on deletion

   Retain means the volume and data stay after claim deletion for manual handling.

3. Final Answer:

   The volume is retained and data remains for manual cleanup. -> Option C

4. Quick Check:

   Retain policy = keep volume and data [OK]

Hint: Retain policy keeps volume after claim deletion [OK]

Common Mistakes:

• Assuming data deletes automatically with Retain
• Confusing persistentVolumeReclaimPolicy with reclaimPolicy key
• Thinking volume is backed up automatically

4. You set a PersistentVolume reclaim policy to Delete but after deleting the PersistentVolumeClaim, the volume still exists. What is the most likely cause?

medium

A. The reclaim policy was misspelled in the YAML and ignored.

B. The volume was manually retained by an admin.

C. The PersistentVolumeClaim was not actually deleted.

D. The storage class does not support automatic deletion.

Solution

1. Step 1: Understand Delete reclaim policy

   Delete policy should remove the volume automatically after claim deletion.

2. Step 2: Check storage class support

   If the storage class does not support dynamic deletion, volume remains despite policy.

3. Final Answer:

   The storage class does not support automatic deletion. -> Option D

4. Quick Check:

   Storage class support needed for Delete policy [OK]

Hint: Delete needs storage class support to remove volume [OK]

Common Mistakes:

• Assuming reclaim policy misspelling always causes failure
• Ignoring storage class role in deletion
• Not verifying claim deletion status

5. You want to ensure that when a PersistentVolumeClaim is deleted, the underlying storage is kept intact for backup purposes, but you also want to automate cleanup later. Which reclaim policy should you use and what additional step is needed?

hard

A. Use Retain policy and configure a cleanup job to delete volumes later.

B. Use Delete policy and rely on automatic cleanup only.

C. Use Retain policy and manually delete the volume after backup.

D. Use Delete policy and create snapshots before deletion.

Solution

1. Step 1: Choose policy to keep data after claim deletion

   Retain policy keeps the volume and data safe after claim deletion.

2. Step 2: Automate cleanup after backup

   Since Retain does not delete automatically, a cleanup job is needed to remove volumes later.

3. Final Answer:

   Use Retain policy and configure a cleanup job to delete volumes later. -> Option A

4. Quick Check:

   Retain + cleanup job = safe backup + automation [OK]

Hint: Retain keeps data; add cleanup job for automation [OK]

Common Mistakes:

• Assuming Delete keeps data for backup
• Expecting Retain to delete volumes automatically
• Not planning manual or automated cleanup after Retain