Lab
A Cloud Guru

Implement State Persistence for Kubernetes Pods

Part of the power of Kubernetes containers comes from their ephemeral nature. They can be easily created, destroyed, and replaced, and this makes them easy to manage. However, sometimes we need to maintain persistent data that survives beyond the life of a pod. In this lab, we will go through how to implement state persistence using PersistentVolumes and PersistentVolume claims. We will create persistent storage and consume it using a pod.

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Path Info

Level

Intermediate

Duration

1h 0m

Published

Mar 31, 2019

Challenge

Create a PersistentVolume

Create a descriptor file with vi mysql-pv.yml:

kind: PersistentVolume
apiVersion: v1
metadata:
  name: mysql-pv
spec:
  storageClassName: localdisk
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data"

Create the PersistentVolume.

kubectl apply -f mysql-pv.yml

Challenge

Create a PersistentVolumeClaim

Create a descriptor file with vi mysql-pv-claim.yml:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim
spec:
  storageClassName: localdisk
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 500Mi

Create the PersistentVolumeClaim:

kubectl apply -f mysql-pv-claim.yml

Challenge

Create a MySQL Pod configured to use the PersistentVolumeClaim
Create a descriptor file with vi mysql-pod.yml:
```
apiVersion: v1
kind: Pod
metadata:
  name: mysql-pod
spec:
  containers:
  - name: mysql
    image: mysql:5.6
    ports:
    - containerPort: 3306
    env:
    - name: MYSQL_ROOT_PASSWORD
      value: password
    volumeMounts:
    - name: mysql-storage
      mountPath: /var/lib/mysql
  volumes:
  - name: mysql-storage
    persistentVolumeClaim:
      claimName: mysql-pv-claim
```
Create the Pod:
```
kubectl apply -f mysql-pod.yml
```
Check the status of the pod with kubectl get pod mysql-pod. After a few moments it should be in the RUNNING status.

You can also verify that the pod is interacting with the filesystem at /mnt/data on the node. Log in to the node from the Kube master like this, using the same as the password for the kube master:
```
ssh [email protected]
```
Check the contents of the PersistentVolume directory:
```
ls /mnt/data
```
You should see files and directories there related to MySQL. These were created by the pod, meaning that your PersistentVolume and PersistentVolumeClaim are working!

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

What's a lab?

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.