Kubernetes is an open-source container orchestration system for automating the deployment, scaling, and management of containerized applications. It was developed by Google and is now maintained by the Cloud Native Computing Foundation.

Kubernetes provides a platform-agnostic way of managing containerized applications, making it easy to deploy and scale applications across different environments, such as on-premises, in the cloud, or across different cloud providers. It provides a number of features that make it easy to manage containerized applications, including automatic scaling, self-healing, and rolling updates.

Kubernetes uses a declarative configuration model, which means that users specify the desired state of their application, and Kubernetes ensures that the actual state of the application matches the desired state. Kubernetes also provides robust security features, such as role-based access control and network segmentation, to help protect applications and data.

Overall, Kubernetes allows for the efficient and streamlined management of containerized applications, making it a popular choice for organizations of all sizes and industries.

Deploying WordPress on Kubernetes

Now, to deploy WordPress using Kubernetes, here are the steps you need to follow;

Setting up a Kubernetes Cluster

Before deploying WordPress, you will need to have a Kubernetes cluster set up. You can use a cloud provider like Google Kubernetes Engine (GKE) or Amazon Elastic Kubernetes Service (EKS) to create a cluster. Alternatively, you can set up a cluster on your own using tools like Minikube or kubeadm.

Deploying WordPress

Once you have a cluster set up, you can deploy WordPress to it. One way to do this is to use a Helm chart to install WordPress. Helm is a package manager for Kubernetes that allows you to easily install and manage applications. You can use the official WordPress Helm chart to deploy WordPress to your cluster.

Creating a MySQL Database

Before deploying WordPress, you will also need to create a MySQL database. You can use a Kubernetes deployment to create a MySQL pod, and then use a Kubernetes service to expose the pod to the WordPress deployment. Here is an example of a YAML file that creates a MySQL deployment, service and Persistent Volume Claim (PVC);

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - name: mysql
        image: mysql:5.7
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        - name: MYSQL_USER
          value: "wordpress"
        - name: MYSQL_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: wordpress-password
        - name: MYSQL_DATABASE
          value: "wordpress"
        ports:
        - containerPort: 3306
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pv-claim
---
apiVersion: v1
kind: Service
metadata:
  name: mysql
spec:
  selector:
    app: mysql
  ports:
  - name: mysql
    port: 3306
    targetPort: 3306
  type: ClusterIP
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim

This YAML file is used to create a Kubernetes deployment, service, and Persistent Volume Claim (PVC) for a MySQL instance that will be used by WordPress.

• apiVersion: Indicates the version of the Kubernetes API that this resource belongs to. In this case, apps/v1 is used, which is the version for Deployments.
• kind: Indicates the type of resource that this YAML file is creating. In this case, Deployment is used, which creates a deployment resource that ensures a specified number of replicas of a pod are running at all times.
• metadata: Contains information about the resource, such as its name. In this case, the name of the deployment is mysql.
• spec: Contains the configuration for the resource. For a deployment, it includes the number of replicas, the selector that specifies which pods to include in the deployment, and the template that describes the pod.
• replicas: Specifies the number of replicas of the pod that should be running at all times. In this case, the value is 1, which means that there should always be one replica of the MySQL pod running.
• selector: Specifies which pods to include in the deployment. In this case, the selector matches pods that have the label app: mysql.
• template: Describes the pod that should be created by the deployment. In this case, the pod includes a container named mysql that runs the MySQL image version 5.7.
• env: Specifies the environment variables that should be passed to the container. In this case, it includes the MYSQL_ROOT_PASSWORD, MYSQL_USER, MYSQL_PASSWORD, and MYSQL_DATABASE. The values for the passwords and the user are taken from the secret created previously.
• ports: Specifies the ports that should be exposed by the container. In this case, the container port 3306 is exposed.
• volumeMounts: Specifies the storage volumes that should be mounted into the container. In this case, it mounts the volume named mysql-persistent-storage to the path /var/lib/mysql in the container.
• volumes: Specifies the storage volumes that should be created for the pod. In this case, it creates a volume named mysql-persistent-storage that is backed by the PVC named mysql-pv-claim.

After the deployment, it creates a service to expose the deployment to the network and a PVC to store the data in a persistent way.

Configuring WordPress

After the WordPress and MySQL pods are running, you will need to configure the WordPress installation. You can do this by setting environment variables or by using a ConfigMap to store the configuration.

Configuring Domain Name

Setting up DNS Records

Once WordPress is deployed, you will need to set up DNS records to point your domain name to the IP of your Kubernetes cluster. You can do this by creating an A record that points to the IP of your load balancer or ingress controller.

Configuring Ingress

Once you have set up your DNS records, you will need to configure an ingress to handle traffic to your domain name. An ingress is a Kubernetes resource that allows you to route incoming traffic to different services in your cluster based on the hostname or path of the request.

Creating an Ingress Resource

To create an ingress resource, you will need to create a YAML file that defines the ingress and the rules for routing traffic. You can use the ingress-nginx ingress controller to handle the ingress traffic.

Updating the Ingress

Rules Once the ingress resource is created, you will need to update the ingress rules to route traffic to the WordPress service. You will need to specify the hostname and path for the ingress rules, and also configure the ingress to use the correct ingress controller.

Please note that these are a general steps and details may vary depending on the specific setup and environment.