Reclaim policies (Retain, Delete) in Kubernetes - Mini Project: Build & Apply

Understanding Kubernetes PersistentVolume Reclaim Policies

📖 Scenario: You are managing storage in a Kubernetes cluster. You want to understand how PersistentVolumes behave when their associated PersistentVolumeClaims are deleted. This depends on the reclaimPolicy set on the PersistentVolume.There are two main reclaim policies: Retain and Delete. Retain keeps the volume and data after the claim is deleted, while Delete removes the volume and data.

🎯 Goal: Create a Kubernetes PersistentVolume manifest with a reclaimPolicy set to Retain. Then create another PersistentVolume manifest with reclaimPolicy set to Delete. Finally, print the reclaim policies of both volumes to understand their behavior.

📋 What You'll Learn

Create a PersistentVolume named pv-retain with reclaimPolicy Retain

Create a PersistentVolume named pv-delete with reclaimPolicy Delete

Store the reclaim policies in variables named retain_policy and delete_policy

Print the values of retain_policy and delete_policy

💡 Why This Matters

🌍 Real World

Kubernetes administrators use reclaim policies to control what happens to storage volumes when applications stop using them. This helps prevent accidental data loss or frees up storage automatically.

💼 Career

Understanding reclaim policies is essential for DevOps engineers and cloud administrators managing persistent storage in Kubernetes clusters.

1

Create PersistentVolume with reclaimPolicy Retain

Create a dictionary called pv_retain representing a Kubernetes PersistentVolume manifest with these exact fields: metadata.name set to pv-retain, spec.capacity.storage set to 10Gi, spec.accessModes set to ["ReadWriteOnce"], spec.persistentVolumeReclaimPolicy set to Retain, and spec.hostPath.path set to /mnt/data-retain.

Kubernetes

# Create the pv_retain dictionary with the specified fields
# Your code here

Need a hint?

Use nested dictionaries to represent the manifest structure. The reclaim policy is under spec.persistentVolumeReclaimPolicy.

2

Create PersistentVolume with reclaimPolicy Delete

Create a dictionary called pv_delete representing a Kubernetes PersistentVolume manifest with these exact fields: metadata.name set to pv-delete, spec.capacity.storage set to 10Gi, spec.accessModes set to ["ReadWriteOnce"], spec.persistentVolumeReclaimPolicy set to Delete, and spec.hostPath.path set to /mnt/data-delete.

Kubernetes

pv_retain = {
    "apiVersion": "v1",
    "kind": "PersistentVolume",
    "metadata": {
        "name": "pv-retain"
    },
    "spec": {
        "capacity": {
            "storage": "10Gi"
        },
        "accessModes": ["ReadWriteOnce"],
        "persistentVolumeReclaimPolicy": "Retain",
        "hostPath": {
            "path": "/mnt/data-retain"
        }
    }
}

# Create the pv_delete dictionary with the specified fields
# Your code here

Need a hint?

Follow the same structure as pv_retain, but change the name and reclaim policy accordingly.

3

Extract reclaim policies into variables

Create two variables: retain_policy and delete_policy. Assign retain_policy the value of pv_retain["spec"]["persistentVolumeReclaimPolicy"] and delete_policy the value of pv_delete["spec"]["persistentVolumeReclaimPolicy"].

Kubernetes

pv_retain = {
    "apiVersion": "v1",
    "kind": "PersistentVolume",
    "metadata": {
        "name": "pv-retain"
    },
    "spec": {
        "capacity": {
            "storage": "10Gi"
        },
        "accessModes": ["ReadWriteOnce"],
        "persistentVolumeReclaimPolicy": "Retain",
        "hostPath": {
            "path": "/mnt/data-retain"
        }
    }
}

pv_delete = {
    "apiVersion": "v1",
    "kind": "PersistentVolume",
    "metadata": {
        "name": "pv-delete"
    },
    "spec": {
        "capacity": {
            "storage": "10Gi"
        },
        "accessModes": ["ReadWriteOnce"],
        "persistentVolumeReclaimPolicy": "Delete",
        "hostPath": {
            "path": "/mnt/data-delete"
        }
    }
}

# Extract reclaim policies into variables
# Your code here

Need a hint?

Access nested dictionary keys step-by-step to get the reclaim policy values.

4

Print reclaim policies

Write two print statements to display the values of retain_policy and delete_policy exactly as: print("Retain policy:", retain_policy) and print("Delete policy:", delete_policy).

Kubernetes

pv_retain = {
    "apiVersion": "v1",
    "kind": "PersistentVolume",
    "metadata": {
        "name": "pv-retain"
    },
    "spec": {
        "capacity": {
            "storage": "10Gi"
        },
        "accessModes": ["ReadWriteOnce"],
        "persistentVolumeReclaimPolicy": "Retain",
        "hostPath": {
            "path": "/mnt/data-retain"
        }
    }
}

pv_delete = {
    "apiVersion": "v1",
    "kind": "PersistentVolume",
    "metadata": {
        "name": "pv-delete"
    },
    "spec": {
        "capacity": {
            "storage": "10Gi"
        },
        "accessModes": ["ReadWriteOnce"],
        "persistentVolumeReclaimPolicy": "Delete",
        "hostPath": {
            "path": "/mnt/data-delete"
        }
    }
}

retain_policy = pv_retain["spec"]["persistentVolumeReclaimPolicy"]
delete_policy = pv_delete["spec"]["persistentVolumeReclaimPolicy"]

# Print the reclaim policies
# Your code here

Need a hint?

Use print with a string and the variable separated by a comma to display the policy names.