How to Run WordPress on a Kubernetes Cluster from Scratch

Prerequisites

1- Ubuntu 16.04 EC2 Instance
2- Memory- 8 GB
3-Type- T2 Medium
4-Security Group — All TCP open

Step 1— Set up each server in the cluster to run Kubernetes

SSH to each of the servers you created. Proceed with executing the following commands as root. You may become the root user by executing sudo -i after SSH-ing to each host.

On each of the three Ubuntu 16.04 servers run the following commands as root:

apt-get update && apt-get install -y apt-transport-https
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF
apt-get update
apt-get install -y kubelet=1.15.4–00 kubeadm=1.15.4–00 kubectl=1.15.4–00 docker.io

Step 2— Setup the Kubernetes Master

On the Master Machine run the following command:

kubeadm init

The output look like this as shown below

This can take a minute or two to run, the result will look like this:

To start using your cluster, you need to run the following as a regular user:

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Run the following command to check the status of the master

kubectl get nodes

The output looks like this as shown below. Here Master is not ready as network plugin is not installed.

Step 3— Setup a Kubernetes Add-On For Networking Features And Policy

Kubernetes Add-Ons are pods and services that implement cluster features. Pods extend the functionality of Kubernetes. You can install addons for a range of cluster features including Networking and Visualization.

We are going to install the Weave Net Add-On on the kube-01 master which provides networking and network policy, will carry on working on both sides of a network partition, and does not require an external database. Read more about the Weave Net Add-on in the Weave Works Docs.

Next you will deploy a pod network to the cluster.

The options are listed at: https://kubernetes.io/docs/concepts/cluster-administration/addons/

Installing the Weave Net Add-On

Get the Weave Net yaml:

curl -o weave.yaml https://cloud.weave.works/k8s/v1.8/net.yaml
kubectl apply -f weave.yaml

The output looks like this after running above two commands

Check the status of master by using the following command and now the master is ready

kubectl get nodes

kubectl get pods — all-namespaces

Step 3b— Resolve Taint for single node master (optional) when only one master exists and no worker loads

Run the following command to describe the nodes.

Note: To get the namespace, Using the command kubectl get nodes

kubectl describe nodes <Namespace>

apt-get install jq

Untaint the node

kubectl taint nodes --all node-role.kubernetes.io/master-

Check the status of the taint by running the following command

kubectl describe nodes <Namespace>

Step 4— WordPress Setup

Once we have our cluster up and running, time to make it work for us. The first thing to know is that every node will talk to the master using Kubectl which is a binary package that we installed earlier in the tutorial.

WordPress would require a persistent volume (a volume which doesn’t get destroyed over reboots or deletion of applications) this volume will be used by mysql for maintaining various databases to be used by WordPress. To do that, open a file persistent-volume.yaml using any terminal text editor that you prefer. Then enter the following contents in the file:

Here we are setting the following values

PersistentVolume

local-pv-1 storage: 3Gi
local-pv-2 storage: 2Gi

vi local-volumes.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: local-pv-1
  labels:
    type: local
spec:
  capacity:
    storage: 3Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /tmp/data/pv-1
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: local-pv-2
  labels:
    type: local
spec:
  capacity:
    storage: 2Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /tmp/data/pv-2

After this is saved, in the same directory as this file, run the command:

kubectl create -f local-volumes.yaml

This file consists instructions for creating two persistent volumes. To see if this has indeed worked, run:

kubectl get pv

Once the status shows that the volumes are available, let’s move on to creating a secret which would be used to store your mysql password. Replace the YOUR_PASSWORD field with your secure password.

kubectl create secret generic mysql-pass --from-literal=password=YOUR_PASSWORD

The mysql-pass object is what holds the secret now, and we shall use it to deploy mysql by first creating a file called mysql-deployment.yaml

vi mysql-deployment.yaml

Here we are setting the following values

PersistentVolumeClaim

mysql-pv-claim: 2Gi

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: 2Gi
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: wordpress-mysql
  labels:
    app: wordpress
spec:
  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

That file would kick in the mysql database if you run:

kubectl create -f mysql-deployment.yaml

Finally, we are ready for our WordPress installation. Create a wordpress-deployment.yaml file:

vi wordpress-deployment.yaml

Here we are setting the following values

PersistentVolumeClaim

wordpress: 1Gi

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: 1Gi
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: wordpress
  labels:
    app: wordpress
spec:
  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

After creating the above file, run:

kubectl create -f wordpress-deployment.yaml

Check the status of the pods by running the following command

kubectl get pods -o wide

Now check the status of the service by using the following command

kubectl get svc

Go to your browser and use your public IP address (mine is 3.236.140.2) followed by wordpress port . Here wordpress port is 31546 as shown in the above pic.

http://3.236.140.2:31546/

In the below picture 1 is for public ip and 2 is your port number for wordpress

wordpress Homepage