How to Deploy a WordPress using Kubernetes

When deploying WordPress on Kubernetes, you’ll need to create several YAML files to configure the various components needed for a WordPress site. Kubernetes uses these YAML files to define, configure, and manage the deployment of containerized applications. For WordPress, the essential components include a web server (WordPress itself), a database (MySQL or MariaDB), and persistent storage for both. Here’s a step-by-step guide to writing the necessary YAML files to get WordPress up and running on Kubernetes.

1. PersistentVolume (PV) and PersistentVolumeClaim (PVC)

Persistent volumes are used to store persistent data like the WordPress content and the database files. PVCs are requests for storage by a user.

WordPress PV and PVC

kind: PersistentVolume
apiVersion: v1
metadata:
  name: wordpress-pv
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data/wordpress"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: wordpress-pvc
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

Database PV and PVC

kind: PersistentVolume
apiVersion: v1
metadata:
  name: mysql-pv
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data/mysql"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: mysql-pvc
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

2. MySQL Deployment

You need to deploy MySQL as the database for WordPress. This involves creating a deployment and a service.

MySQL Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  selector:
    matchLabels:
      app: wordpress
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: wordpress
    spec:
      containers:
      - image: mysql:5.7
        name: mysql
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: yourpassword
        - name: MYSQL_DATABASE
          value: wordpress
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pvc

MySQL Service

apiVersion: v1
kind: Service
metadata:
  name: mysql
spec:
  ports:
  - port: 3306
  selector:
    app: wordpress
  clusterIP: None

3. WordPress Deployment and Service

Finally, deploy WordPress and expose it through a service.

WordPress Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: wordpress
spec:
  selector:
    matchLabels:
      app: wordpress
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: wordpress
    spec:
      containers:
      - image: wordpress:latest
        name: wordpress
        env:
        - name: WORDPRESS_DB_HOST
          value: mysql
        - name: WORDPRESS_DB_PASSWORD
          value: yourpassword
        ports:
        - containerPort: 80
          name: wordpress
        volumeMounts:
        - name: wordpress-persistent-storage
          mountPath: /var/www/html
      volumes:
      - name: wordpress-persistent-storage
        persistentVolumeClaim:
          claimName: wordpress-pvc

WordPress Service

apiVersion: v1
kind: Service
metadata:
  name: wordpress
spec:
  ports:
  - port: 80
  selector:
    app: wordpress
  type: LoadBalancer

Deployment Steps

1. Create the Persistent Volumes and Claims: Apply the PV and PVC configurations first to ensure the storage is available for the deployments.
2. Deploy MySQL: Next, apply the MySQL deployment and service YAML files. This step sets up the database WordPress will use.
3. Deploy WordPress: Finally, apply the WordPress deployment and service YAML files. This step will set up WordPress and connect it to the previously deployed MySQL database.

Use the kubectl apply -f <filename>.yaml command to apply each of these