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Scalable WordPress deployment on Kubernetes Cluster

This journey showcases the full power of Kubernetes clusters and shows how can we deploy the world's most popular website framework on top of world's most popular container orchestration platform. We provide a full roadmap for hosting WordPress on Kubernetes Cluster. Each component runs in a separate container or group of containers.

WordPress represents a typical multi-tier app and each component will have its own container(s). The WordPress containers will be the frontend tier and the MySQL container will be the database/backend tier for WordPress.

In addition to deployment on Kubernetes, we will also show how you can scale the front WordPress tier, as well as how you can use MySQL as a service from Bluemix to be used by WordPress frontend.

Included Components

• WordPress (Latest)
• MySQL (5.6)
• Kubernetes Clusters
• Bluemix container service
• Bluemix Compose for MySQL
• Bluemix DevOps Toolchain Service

Prerequisite

Create a Kubernetes cluster with either Minikube for local testing, or with IBM Bluemix Container Service to deploy in cloud. The code here is regularly tested against Kubernetes Cluster from Bluemix Container Service using Travis.

Objectives

This scenario provides instructions for the following tasks:

• Create local persistent volumes to define persistent disks.
• Create a secret to protect sensitive data.
• Create and deploy the WordPress frontend with one or more pods.
• Create and deploy the MySQL database(either in a container or using Bluemix MySQL as backend).

Deploy to Bluemix

If you want to deploy the wordpress directly to Bluemix, click on 'Deploy to Bluemix' button below to create a Bluemix DevOps service toolchain and pipeline for deploying the WordPress sample, else jump to Steps

Please follow the Toolchain instructions to complete your toolchain and pipeline.

Steps

1. Setup MySQL Secrets
2. Create local persistent volumes
3. Create Services and Deployments for WordPress and MySQL

• 3.1 Using MySQL in container
• 3.2 Using Bluemix MySQL

4. Accessing the external WordPress link
5. Using WordPress

1. Setup MySQL Secrets

Quickstart option: In this repository, run bash scripts/quickstart.sh.

Create a new file called password.txt in the same directory and put your desired MySQL password inside password.txt (Could be any string with ASCII characters).

We need to make sure password.txt does not have any trailing newline. Use the following command to remove possible newlines.

tr -d '\n' <password.txt >.strippedpassword.txt && mv .strippedpassword.txt password.txt

2. Create Local Persistent Volumes

To save your data beyond the lifecycle of a Kubernetes pod, you will want to create persistent volumes for your MySQL and Wordpress applications to attach to.

For "lite" IBM Bluemix Container Service

Create the local persistent volumes manually by running

kubectl create -f local-volumes.yaml

For paid IBM Bluemix Container Service OR Minikube

Persistent volumes are created dynamically for you when the MySQL and Wordpress applications are deployed. No action is needed.

3. Create Services and deployments for WordPress and MySQL

3.1 Using MySQL in container

Note: If you want to use Bluemix Compose-MySql as your backend, please go to Using Bluemix MySQL as backend.

Install persistent volume on your cluster's local storage. Then, create the secret and services for MySQL and WordPress.

kubectl create secret generic mysql-pass --from-file=password.txt
kubectl create -f mysql-deployment.yaml
kubectl create -f wordpress-deployment.yaml

When all your pods are running, run the following commands to check your pod names.

kubectl get pods

This should return a list of pods from the kubernetes cluster.

NAME                               READY     STATUS    RESTARTS   AGE
wordpress-3772071710-58mmd         1/1       Running   0          17s
wordpress-mysql-2569670970-bd07b   1/1       Running   0          1m

Now please move on to Accessing the External Link.

3.2 Using Bluemix MySQL as backend

Provision Compose for MySQL in Bluemix via https://console.ng.bluemix.net/catalog/services/compose-for-mysql

Go to Service credentials and view your credentials. Your MySQL hostname, port, user, and password are under your credential uri and it should look like this

Modify your wordpress-deployment.yaml file, change WORDPRESS_DB_HOST's value to your MySQL hostname and port(i.e. value: <hostname>:<port>), WORDPRESS_DB_USER's value to your MySQL user, and WORDPRESS_DB_PASSWORD's value to your MySQL password.

And the environment variables should look like this

    spec:
      containers:
      - image: wordpress:4.7.3-apache
        name: wordpress
        env:
        - name: WORDPRESS_DB_HOST
          value: sl-us-dal-9-portal.7.dblayer.com:22412
        - name: WORDPRESS_DB_USER
          value: admin
        - name: WORDPRESS_DB_PASSWORD
          value: XMRXTOXTDWOOPXEE

After you modified the wordpress-deployment.yaml, run the following commands to deploy wordpress.

kubectl create -f wordpress-deployment.yaml

When all your pods are running, run the following commands to check your pod names.

kubectl get pods

This should return a list of pods from the kubernetes cluster.

NAME                               READY     STATUS    RESTARTS   AGE
wordpress-3772071710-58mmd         1/1       Running   0          17s

4. Accessing the external WordPress link

If you have a paid cluster, you can use LoadBalancer instead of NodePort by running

kubectl edit services wordpress

Under spec, change type: NodePort to type: LoadBalancer

Note: Make sure you have service "wordpress" edited shown after editing the yaml file because that means the yaml file is successfully edited without any typo or connection errors.

You can obtain your cluster's IP address using

$ bx cs workers <your_cluster_name>
OK
ID                                                 Public IP        Private IP     Machine Type   State    Status   
kube-hou02-pa817264f1244245d38c4de72fffd527ca-w1   169.47.220.142   10.10.10.57    free           normal   Ready 

You will also need to run the following command to get your NodePort number.

$ kubectl get svc wordpress
NAME        CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE
wordpress   10.10.10.57   <nodes>       80:30180/TCP   2m

Congratulation. Now you can use the link http://[IP]:[port number] to access your WordPress site.

Note: For the above example, the link would be http://169.47.220.142:30180

You can check the status of your deployment on Kubernetes UI. Run kubectl proxy and go to URL 'http://127.0.0.1:8001/ui' to check when the WordPress container becomes ready.

Note: It can take up to 5 minutes for the pods to be fully functioning.

(Optional) If you have more resources in your cluster, and you want to scale up your WordPress website, you can run the following commands to check your current deployments.

$ kubectl get deployments
NAME              DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
wordpress         1         1         1            1           23h
wordpress-mysql   1         1         1            1           23h

Now, you can run the following commands to scale up for WordPress frontend.

$ kubectl scale deployments/wordpress --replicas=2
deployment "wordpress" scaled
$ kubectl get deployments
NAME              DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
wordpress         2         2         2            2           23h
wordpress-mysql   1         1         1            1           23h

As you can see, we now have 2 pods that are running the WordPress frontend.

Note: If you are a free tier user, we recommend you only scale up to 10 pods since free tier users have limited resources.

5. Using WordPress

Now that WordPress is running you can register as a new user and install WordPress.

After installing WordPress, you can post new comments.

Troubleshooting

If you accidentally created a password with newlines and you can not authorize your MySQL service, you can delete your current secret using

kubectl delete secret mysql-pass

If you want to delete your services, deployments, and persistent volume claim, you can run

kubectl delete deployment,service,pvc -l app=wordpress

If you want to delete your persistent volume, you can run the following commands

kubectl delete -f local-volumes.yaml

If wordpress is taking a long time, you can debug it by inspecting the logs

kubectl get pods # Get the name of the wordpress pod
kubectl logs [wordpress pod name]

References

• This WordPress example is based on Kubernetes's open source example mysql-wordpress-pd at https://github.com/kubernetes/kubernetes/tree/master/examples/mysql-wordpress-pd.

License

Apache 2.0