Setup WordPress and MySQL on Kubernetes Cluster

This setup will help us to understand how to configure a multi-tier web application on Kubernetes. In this example, we will launch a WordPress container and MySQL container. But first, you need the Kubernetes cluster ready with you, If you don’t have it then follow this article:

How to use Ansible playbooks for configuring the Kubernetes cluster on AWS?

After having the Kubernetes cluster ready go to the control plan/master node for creating this structure. Now, just follow these simple steps:

Step 1: PVC and PV

Here, PV stands for Persistent Volume. PV is nothing but just a storage that comes from different locations like clouds or networks or the control plan itself. PVC stands for Persistent Volume Claim. PVC helps to claim the PV from the Kubernetes dynamically. If you wanted to know more about it then just go to this site:

Persistent Volumes

We need PV for MySQL image for creating the database. First, a folder to share and then create a PV, here is a code for it.

mkdir /root/data

Create a file called persistent-volume.yaml with the following code, you can give any name to the file, it depends on you.

apiVersion: v1
kind: PersistentVolume
metadata:
  name: wp-pv
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/root/data"

kubectl apply -f persistent-volume.yaml

The above-given command will create a PV with wp-pv name and 1 GiB storage. For checking the details about run the following command:

kubectl get pv wp-pv

Now, let’s create PVC. Create the file called persistent-volume-claim.yaml and paste the following code.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: wp-pv-claim
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

Run the following command:

kubectl apply -f persistent-volume-claim.yaml

This PVC claims the storage from the PV that we created before in this article.

kubectl get pvc wp-pv-claim

Step 2: Create a MySQL deployment

apiVersion: v1
kind: Service
metadata:
  name: wordpress-mysql
  labels:
    app: wordpress
spec:
  ports:
    - port: 3306
  selector:
    app: wordpress
    tier: mysql
  clusterIP: None
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: wordpress-mysql
  labels:
    app: wordpress
spec:
  selector:
    matchLabels:
      app: wordpress
      tier: mysql
  template:
    metadata:
      labels:
        app: wordpress
        tier: mysql
    spec:
      containers:
      - image: mysql:5.6
        name: mysql
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: <password>
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: wp-pv-claim

Create a file with mysql-deployment.yaml name. In this deployment, I have used mysql:5.6 MySQL image. MySQL image has some environmental variables that we have to mention like MYSQL_ROOT_PASSWORD for the database password, also we have to create the service for it and attach PV with it.

kubectl apply -f mysql-deployment.yaml

Step 3: Create a WordPress deployment

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: wordpress
  labels:
    app: wordpress
spec:
  selector:
    matchLabels:
      app: wordpress
      tier: frontend
  template:
    metadata:
      labels:
        app: wordpress
        tier: frontend
    spec:
      containers:
      - image: wordpress:4.8-apache
        name: wordpress
        env:
        - name: WORDPRESS_DB_HOST
          value: wordpress-mysql
        - name: WORDPRESS_DB_PASSWORD
          value: <wordpress_db_password>
        ports:
        - containerPort: 80
          name: wordpress

Create a file called wordpress-deployment.yaml. This wordpress:4.8-apache image also has some env like WORDPRESS_DB_HOST and WORDPRESS_DB_PASSWORD.

kubectl apply -f wordpress-deployment.yaml

But we can’t access it directly, we need a service that can expose it to the public world, so run this command to expose this deployment:

kubectl expose deployment Wordpress --port=80 --type=NodePort

kubectl get svc wordpress

Now, we can access the site with http://[public-ip-master]:30694.

That’s all. You can install WordPress as you can.

Thank you for reading the article.