Why persistent storage matters in Kubernetes - See It in Action

Why persistent storage matters in Kubernetes

📖 Scenario: You are managing a Kubernetes cluster that runs applications needing to save data permanently. You want to understand how to set up storage that keeps data safe even if containers restart or move.

🎯 Goal: Learn how to create a PersistentVolumeClaim in Kubernetes and use it in a Pod to keep data persistent across container restarts.

📋 What You'll Learn

Create a PersistentVolumeClaim named my-pvc requesting 1Gi of storage

Create a Pod named storage-demo that uses the my-pvc volume

Mount the volume inside the Pod at /data

Verify the Pod can write and read data from the persistent volume

💡 Why This Matters

🌍 Real World

Applications like databases, content management systems, and file servers need persistent storage to keep data safe even if containers restart or move to other nodes.

💼 Career

Understanding persistent storage in Kubernetes is crucial for DevOps engineers and cloud administrators to ensure data durability and application reliability.

1

Create a PersistentVolumeClaim

Write a YAML manifest to create a PersistentVolumeClaim named my-pvc that requests 1Gi of storage with access mode ReadWriteOnce.

Kubernetes

# Write the PersistentVolumeClaim YAML manifest here
# Your code here

Need a hint?

Use kind: PersistentVolumeClaim and specify storage: 1Gi under resources.requests.

2

Create a Pod that uses the PersistentVolumeClaim

Write a YAML manifest to create a Pod named storage-demo that mounts the PersistentVolumeClaim my-pvc as a volume named mypvc-volume inside the container at path /data. Use the image busybox and keep the container running with sleep 3600.

Kubernetes

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

# Write the Pod YAML manifest here
# Your code here

Need a hint?

Define a Pod with a container that mounts the volume from my-pvc at /data.

3

Write data inside the Pod to the persistent volume

Use kubectl exec to run the command echo 'Hello Kubernetes' > /data/message.txt inside the storage-demo Pod to write data to the persistent volume.

Kubernetes

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
---
apiVersion: v1
kind: Pod
metadata:
  name: storage-demo
spec:
  containers:
  - name: busybox
    image: busybox
    command: ["sleep", "3600"]
    volumeMounts:
    - name: mypvc-volume
      mountPath: /data
  volumes:
  - name: mypvc-volume
    persistentVolumeClaim:
      claimName: my-pvc

# Run the kubectl exec command below
# Your code here

Need a hint?

Use kubectl exec with sh -c to write the text into /data/message.txt.

4

Read the data back from the persistent volume

Use kubectl exec to run cat /data/message.txt inside the storage-demo Pod and print the output to verify the data is saved persistently.

Kubernetes

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
---
apiVersion: v1
kind: Pod
metadata:
  name: storage-demo
spec:
  containers:
  - name: busybox
    image: busybox
    command: ["sleep", "3600"]
    volumeMounts:
    - name: mypvc-volume
      mountPath: /data
  volumes:
  - name: mypvc-volume
    persistentVolumeClaim:
      claimName: my-pvc

kubectl exec storage-demo -- sh -c "echo 'Hello Kubernetes' > /data/message.txt"

# Run the kubectl exec command to read the file below
# Your code here

Need a hint?

Use kubectl exec storage-demo -- cat /data/message.txt to read and print the file content.