Deploying WordPress and MySQL with durable storage in a K8S cluster (Terraform/Minikube/AWS/MySQL/Wordpress)

Deploying a WordPress site and a MySQL database using Minikube. Both applications use PersistentVolumes and PersistentVolumeClaims to store data.

Minikube is a tool that lets you run Kubernetes locally, it runs a single-node Kubernetes cluster on your personal computer (including Windows, macOS and Linux PCs) so that you can try out Kubernetes, or for daily development work.

A PersistentVolume (PV) is a piece of storage in the cluster that has been manually provisioned by an administrator, or dynamically provisioned by Kubernetes using a StorageClass.

A PersistentVolumeClaim (PVC) is a request for storage by a user that can be fulfilled by a PV. PersistentVolumes and PersistentVolumeClaims are independent from Pod life cycles and preserve data through restarting, rescheduling, and even deleting Pods.

FOLLOWING ARE THE STEPS TO ACHIEVE THE TARGET:

1. Create a yaml file (pvc.yml) for pvc with ReadWriteOnce as the access mode and 10Gi as permanent storage space from the central storage

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysqlpvc1
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests: 10Gi

2. Create a yaml file (wp.yml) for the replica set so as when the system crashes and pods get deleted another replica of the same pod is launched automatically for wordpress.

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: wprs1

spec:
  replicas: 1
  selector:
    matchLabels:
      env: dev
      app: wp
  template:
    metadata:
      name: wppod1
      labels:
        env: dev
        app: wp
    spec:
      containers:
      - name: "wpcon1"

3. Create a yaml file (mysql.yml) for the replica set so as when the system crashes and pods get deleted another replica of the same pod is launched automatically for mysql.

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: mysqlrs1

spec:
  replicas: 1
  selector:
    matchLabels:
      env: dev
  template:
    metadata:
      name: mysqlpod1
      labels:
        env: dev
    spec:
      containers:
      - name: "mysqlcon1"
        image: "mysql:5.6"
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
              secretKeyRef: 
               name: mysqlsecret 
               key: rpass
        - name: MYSQL_DATABASE
          value: mylwdb
        - name: MYSQL_USER
          valueFrom:
              secretKeyRef: 
               name: mysqlsecret 
               key: username
        - name: MYSQL_PASSWORD
          valueFrom:
              secretKeyRef: 
               name: mysqlsecret 
               key: vpass
        volumeMounts:
         - name: web-vol1
           mountPath:  /var/lib/mysql
      volumes:
       - name: web-vol1 
         persistentVolumeClaim:

4. Create a yaml file for the deployment of mysql with no connectivity with outside world.

apiVersion: v1
kind: Service
metadata:
  name: wordpress-mysql
  labels:
    app: wordpress
spec:
  ports:
    - port: 3306
  selector:
    app: wordpress
    tier: mysql
  clusterIP: None
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim
  labels:
    app: wordpress
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: wordpress-mysql
  labels:
    app: wordpress
spec:
  selector:
    matchLabels:
      app: wordpress
      tier: mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: wordpress
        tier: mysql
    spec:
      containers:
      - image: mysql:5.6
        name: mysql
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-pass
              key: password
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pv-claim

5. Create a yaml file for the deployment of wordpress with load balancer as service

apiVersion: v1
kind: Service
metadata:
  name: wordpress
  labels:
    app: wordpress
spec:
  ports:
    - port: 80
  selector:
    app: wordpress
    tier: frontend
  type: LoadBalancer
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: wp-pv-claim
  labels:
    app: wordpress
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: wordpress
  labels:
    app: wordpress
spec:
  selector:
    matchLabels:
      app: wordpress
      tier: frontend
  strategy:
    type: Recreate
  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
          valueFrom:
            secretKeyRef:
              name: mysql-pass
              key: password
        ports:
        - containerPort: 80
          name: wordpress
        volumeMounts:
        - name: wordpress-persistent-storage
          mountPath: /var/www/html
      volumes:
      - name: wordpress-persistent-storage
        persistentVolumeClaim:
          claimName: wp-pv-claim

6. A secret file to save key-value pairs.

apiVersion: v1
kind: Secret
metadata:
  name: mysqlsecret
data:
   username: ##
   vpass: ##

7. A kustomization file to be created for the complete deployment and run with the command

>kubectl create -k .
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
secretGenerator:
- name: mysql-pass
  literals:
  - password=redhat
resources:
  - mysql_deployment.yaml
  - wordpress_deployment.yaml

We can get the url of our site by running the following command:

minikube service wordpress --url

The end result should somewhat look like this