WordPress on Kubernetes Cluster — Step-by-Step Guide

Introduction:

WordPress is a popular Content Management System (CMS) that allows you to create and manage websites easily. Kubernetes is a powerful container orchestration platform that can help you deploy and manage WordPress with high availability and scalability.

This guide will walk you through setting up WordPress on a Kubernetes cluster using a MySQL StatefulSet for database storage. We will provide you with the necessary deployment files, secret files, Persistent Volume (PV) and Persistent Volume Claim (PVC) files, and service files to get you started.

Prerequisites:

Before we dive into setting up WordPress on Kubernetes, you’ll need the following prerequisites:

1. A running Kubernetes cluster.
2. kubectl command-line tool configured to interact with your Kubernetes cluster.
3. Helm, a package manager for Kubernetes. You can install Helm by following the official documentation: https://helm.sh/docs/intro/install/ — Optional (for this example not needed)

Step 1: Create MySQL StatefulSet

We will begin by creating a MySQL StatefulSet. Save the following content to a file named mysql-statefulset.yaml:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
  labels:
    app: mysql
spec:
  replicas: 1
  serviceName: mysql
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - name: database
        image: mysql:5.7
        args:
          - "--ignore-db-dir=lost+found"
        envFrom:
          - secretRef:
              name: mysql-secret
        ports:
        - containerPort: 3306
        volumeMounts:
        - name: mysql-data
          mountPath: /var/lib/mysql
      volumes:
          - name: mysql-data
            persistentVolumeClaim:
              claimName: mysql-pvc

This YAML file defines a MySQL StatefulSet with a single replica, using a Persistent Volume Claim (PVC) for data storage. The MySQL root password is fetched from a secret named mysql-secret.

Step2: Create Mysql Service

---
apiVersion: v1
kind: Service
metadata:
  name: mysql-service
spec:
  ports:
  - port: 3306
    protocol: TCP
  selector:
    app: mysql

Mysql service file is the type of “ClusterIP” because this is for internal communication between MySQL and WordPress

Step 3: Create WordPress Deployment and Service

Now, create a WordPress Deployment YAML file. Save the following content to a file named wordpress-deployment.yaml: Here you have deployment and service files

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: wordpress
spec:
  replicas: 2
  selector:
    matchLabels:
      app: wordpress
  template:
    metadata:
      labels:
        app: wordpress
    spec:
      containers:
        - name: wordpress
          image: wordpress:5.8.3-php7.4-apache
          ports:
            - containerPort: 80
              name: wordpress
          volumeMounts:
            - name: wordpress-data
              mountPath: /var/www/html
          env:
            - name: WORDPRESS_DB_HOST
              value: mysql-service.default.svc.cluster.local
            - name: WORDPRESS_DB_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: mysql-secret
                  key: MYSQL_ROOT_PASSWORD
            - name: WORDPRESS_DB_USER
              value: root
            - name: WORDPRESS_DB_NAME
              value: mysql
      volumes:
        - name: wordpress-data
          persistentVolumeClaim:
            claimName: wordpress-pvc
---
kind: Service
apiVersion: v1
metadata:
  name: wordpress-service
spec:
  type: NodePort
  selector:
    app: wordpress
  ports:
    - name: http
      protocol: TCP
      port: 80
      targetPort: 80
      nodePort: 30007

In this YAML file, we define a WordPress Deployment with two replicas and a corresponding Service to expose WordPress to the outside world with NodePort. You can use the Service type as “LoadBalancer” as well. It uses the MySQL StatefulSet as the database host.

Step 4: Create a Secret for MySQL Password

Create a Secret to securely store the MySQL root password. Save the following content to a file named mysql-secret.yaml:

• First, you have to encode your password with BASE64. Example command is

#echo "mypassword" | base64

• To decode the password you can run the following command:

apiVersion: v1
kind: Secret
metadata:
  name: mysql-secret
type: Opaque
data:
  MYSQL_ROOT_PASSWORD: bXlwYXNzd29yZAo=

Step 5: Create Persistent Volume and Persistent Volume Claim for MySQL and WordPress

To ensure data persistence for both MySQL and WordPress, create Persistent Volumes and Persistent Volume Claims. Create a file named mysql-pv-pvc.yaml with the following content:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-pv
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /mnt/data/mysql

---

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi
  selector:
    matchLabels:
      app: mysql

This YAML file defines a Persistent Volume and a Persistent Volume Claim for MySQL. Ensure the hostPath in the Persistent Volume definition points to a suitable directory on your Kubernetes nodes.

apiVersion: v1
kind: PersistentVolume
metadata:
  name: wordpress-pv
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: manual
  hostPath:
    path: /home/ubuntu/project/wp-data 

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

For this YAML file, we have defined the “/home/ubuntu/project/wp-data” directory to mount with volume

Step 6: Apply the Configurations

Apply the configurations to your Kubernetes cluster using the following commands:

kubectl apply -f mysql-secret.yaml
kubectl apply -f mysql-pv-pvc.yaml
kubectl apply -f mysql-statefulset.yaml
kubectl apply -f mysql-service.yaml
kubectl apply -f wordpress-pv-pvc.yaml
kubectl apply -f wordpress-deployment.yaml

If can apply your all configuration files at a time as well by calling your directory like:

# kubectl apply -f directory_name

Step 6: Access Your WordPress Site

To access your WordPress site, obtain the external IP address of the WordPress Service with the following command:

kubectl get svc wordpress-service

Once you have the external IP address, you can access your WordPress site by navigating to that IP address in your web browser.