WordPress with Portworx on Kubernetes

This reference architecture document shows how you can deploy WordPress, an open-source content management system, with Portworx on Kubernetes. This architecture provides the following benefits:

Portworx enables reliable and persistent storage to ensure WordPress runs with HA
Portworx enables sharedv4 volumes for file uploads
Kubernetes automatically replicates your MySQL data
You can horizontally scale the WordPress container using multi-writer semantics for the file-uploads directory
The cluster automatically repairs itself in the event of a node failure

Prerequisites

You must have a Kubernetes cluster with a minimum of three worker nodes.
Portworx is installed on your Kubernetes cluster. For details about how you can install Portworx on Kubernetes, see the Portworx on Kubernetes page.
You must have Stork installed on your Kubernetes cluster. For details about how you can install Stork, see the Stork page.

Dynamically provision a volume for MySQL

Create a file called mysql-sc.yaml, specifying the following fields and values:
- apiVersion: as storage.k8s.io/v1
- kind: as StorageClass
- metadata.name: with the name of your StorageClass object (this example uses mysql-sc)
- provisioner: as kubernetes.io/portworx-volume. For details about the Portworx-specific parameters, refer to the Portworx Volume section of the Kubernetes website.
- parameters.repl: with the number of replicas Portworx should create (this example creates two replicas)
- parameters.priority_io: with the type of the storage pool (this example uses a high-priority storage pool)
```
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: mysql-sc
provisioner: kubernetes.io/portworx-volume
parameters:
  repl: "3"
  priority_io: "high"
```
For more details about how you can configure a storage class, see the Using Dynamic Provisioning section of the Portworx documentation.
Apply the spec:
```
kubectl apply -f mysql-sc.yaml
```

Create a file called mysql-pvc.yaml with the following content:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pvc
  annotations:
    volume.beta.kubernetes.io/storage-class: mysql-sc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi

NOTE: This PVC references the mysql-sc storage class. As a result, Kubernetes will automatically create a new PVC for each replica.

Apply the spec:
```
kubectl apply -f mysql-pvc.yaml
```

Dynamically provision a volume for WordPress

Create a file called wordpress-sc.yaml with the following content:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: wordpress-sc
provisioner: kubernetes.io/portworx-volume
parameters:
  repl: "3"
  priority_io: "high"
  shared: "true"

NOTE: The sharedv4: "true" flag creates a globally shared namespace volume which can be used by multiple Pods.

Apply the spec:
```
kubectl apply -f wordpress-sc.yaml
```

Create a file called wordpress-pvc.yaml with the following content:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: wp-pvc
  labels:
    app: wordpress
  annotations:
    volume.beta.kubernetes.io/storage-class: wordpress-sc
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Gi

NOTE: This PVC references the wordpress-sc storage class. As a result, Kubernetes will automatically create a new PVC for each replica.

Apply the spec:
```
kubectl apply -f wordpress-pvc.yaml
```

Create a Kubernetes secret for storing your MySQL password

A secret is an object that contains sensitive data. To create a secret, you can use the kubectl create secret command. Note that, to protect your sensitive data, the kubectl get and kubectl describe commands do not display the content of a secret.

Use the echo command to save your MySQL password to a file called ./password.txt, replacing <YOUR-PASSWORD> with your actual password:
```
echo -n '<YOUR-PASSWORD' > ./password.txt
```
To create a new secret, enter the kubectl create secret command, specifying:
- The generic parameter. This instructs Kubernetes to create a secret based on a file, directory, or specified literal value.
- The name of your secret (this example uses mysql-pass)
- The --from-file flag with the name of the file in which you stored your password
```
kubectl create secret generic mysql-pass --from-file=./password.txt
```
Use the kubectl get secrets command to verify that Kubernetes created the secret:
```
kubectl get secrets
```

Deploy MySQL

Create a file named mysql-service.yaml with the following content:

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

Apply the spec:
```
kubectl apply -f mysql-service.yaml
```

Create a file named mysql-deployment.yaml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: wordpress-mysql
  labels:
    app: wordpress
spec:
  selector:
    matchLabels:
      app: wordpress
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: wordpress
        tier: mysql
    spec:
      # Use the Stork scheduler to enable more efficient placement of the pods
      schedulerName: stork
      containers:
      - image: mysql:5.6
        imagePullPolicy:
        name: mysql
        env:
          # $ kubectl create secret generic mysql-pass --from-file=password.txt
          # make sure password.txt does not have a trailing newline
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-pass
              key: password.txt
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pvc

Note the following about this Deployment:

Kubernetes creates a single-instance MySQL database
Kubernetes creates an environment variable called MYSQL_ROOT_PASSWORD that contains your MySQL password
Portworx mounts the Portworx persistent volume in the /var/lib/mysql directory
The Stork scheduler will place your Pods closer to where their data is located

Apply the spec:
```
kubectl apply -f mysql-deployment.yaml
```

Deploy WordPress

Create a file called wordpress-service.yaml with the following content:
```
apiVersion: v1
kind: Service
metadata:
  name: wordpress
  labels:
    app: wordpress
spec:
  ports:
    - port: 80
      nodePort: 30303
  selector:
    app: wordpress
    tier: frontend
  type: NodePort
```
Note that the spec.type field is set to NodePort. Kubernetes exposes the service on each node and makes it accessible from outside the cluster. For more details, see the Type NodePort section of the Kubernetes documentation.
Apply the spec:
```
kubectl apply -f wordpress-service.yaml
```

Create a file called wordpress-deployment.yaml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: wordpress
  labels:
    app: wordpress
spec:
  selector:
    matchLabels:
      app: wordpress
  replicas: 3
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: wordpress
        tier: frontend
    spec:
      # Use the Stork scheduler to enable more efficient placement of the pods
      schedulerName: stork
      containers:
      - image: wordpress:4.8-apache
        name: wordpress
        imagePullPolicy:
        env:
        - name: WORDPRESS_DB_HOST
          value: wordpress-mysql
        - name: WORDPRESS_DB_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-pass
              key: password.txt
        ports:
        - containerPort: 80
          name: wordpress
        volumeMounts:
        - name: wordpress-persistent-storage
          mountPath: /var/www/html
      volumes:
      - name: wordpress-persistent-storage
        persistentVolumeClaim:
          claimName: wp-pvc

Note the following about this Deployment

Portworx will create three replicas of each volume
The Stork scheduler will place your Pods closer to where their data is located
Kubernetes will create an environment variable called WORDPRESS_DB_PASSWORD that contains your MySQL password

Apply the spec:

kubectl apply -f wordpress-deployment.yaml

Validate the cluster functionality

List your Pods:
```
kubectl get pods
```
Display your services:
```
kubectl get services
```

Clean up

Enter the following command to delete the Kubernetes secret:
```
kubectl delete secret mysql-pass
```

Use the kubectl delete to delete your WordPress deployment and PVC:

kubectl delete -f wordpress-deployment.yaml
kubectl delete -f wordpress-pvc.yaml

Use the kubectl delete to delete your MySQL deployment and PVC:

kubectl delete -f mysql-deployment.yaml
kubectl delete -f mysql-pvc.yaml

Discussion Forum

If you have more questions about this application, please head over to our discussion forum and feel free to ask more questions.