Reclaim policies (Retain, Delete) in Kubernetes - Step-by-Step Execution

Process Flow - Reclaim policies (Retain, Delete)

PVC Bound to PV

↓

Delete PVC

↓

Check Reclaim Policy

↓

PV stays

↓

Manual

↓

cleanup

When a PersistentVolumeClaim (PVC) is deleted, Kubernetes checks the PersistentVolume's (PV) reclaim policy. If Retain, the PV stays for manual cleanup. If Delete, the PV and storage are deleted automatically.

Execution Sample

Kubernetes

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-example
spec:
  persistentVolumeReclaimPolicy: Retain

Defines a PersistentVolume with reclaim policy set to Retain, meaning storage is kept after PVC deletion.

Process Table

Step	Action	PVC State	PV State	Reclaim Policy	Result
1	PVC created and bound to PV	Bound	Bound	Retain	PV and PVC linked
2	User deletes PVC	Deleted	Released	Retain	PV released, data intact
3	Admin manually cleans PV	Deleted	Available	Retain	PV ready for reuse
4	PVC created and bound to PV	Bound	Bound	Delete	PV and PVC linked
5	User deletes PVC	Deleted	Released	Delete	PV released, storage deleted

💡 Execution stops after PVC deletion and reclaim policy action completes

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5
PVC State	Not created	Bound	Deleted	Deleted	Bound	Deleted
PV State	Available	Bound	Released	Available	Bound	Released
Reclaim Policy	Set at PV creation	Retain	Retain	Retain	Delete	Delete

Key Moments - 3 Insights

Why does the PV remain after PVC deletion when reclaim policy is Retain?

Because Retain policy tells Kubernetes to keep the PV and data intact for manual cleanup, as shown in step 2 of the execution_table.

What happens to the PV and storage when reclaim policy is Delete?

The PV enters Released state and its storage is deleted automatically when the PVC is deleted, as shown in step 5 of the execution_table.

When does the PV state change to Released?

After PVC deletion with Retain or Delete policy, the PV state changes to Released indicating it is no longer bound but data may remain, as in step 2 and step 5.

Visual Quiz - 3 Questions

Look at the execution_table, what is the PV state immediately after PVC deletion with Retain policy?

A Released

B Deleted

C Bound

D Available

💡 Hint

Check Step 2 in execution_table where PVC is deleted: PV state is Released.

At which step does the PV get deleted automatically?

A Step 3

B Step 4

C Step 5

D Step 2

💡 Hint

Look at Step 5 in execution_table where reclaim policy is Delete and PV is released and storage deleted.

If the reclaim policy was changed from Retain to Delete, what would happen at Step 2?

A PV state changes to Released

B PV and storage get deleted

C PV remains Bound

D PVC remains Bound

💡 Hint

Refer to Step 5 where Delete policy causes PV release and storage deletion after PVC deletion.

Concept Snapshot

Reclaim policies control what happens to storage after PVC deletion.
Retain: PV stays, manual cleanup needed.
Delete: PV released and storage deleted automatically.
Set in PV spec: persistentVolumeReclaimPolicy.
Important for managing storage lifecycle in Kubernetes.

Full Transcript

In Kubernetes, PersistentVolumes (PV) have a reclaim policy that decides what happens when the PersistentVolumeClaim (PVC) using it is deleted. The two main policies are Retain and Delete. When the PVC is deleted, if the policy is Retain, the PV enters the Released state and data is kept safe for manual cleanup. If the policy is Delete, the PV enters Released state and its storage is deleted automatically. This flow helps manage storage resources properly. The execution table shows step-by-step how PVC and PV states change depending on the reclaim policy. Understanding this helps avoid accidental data loss or orphaned storage.

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