How to run WordPress on Google Kubernetes Engine (GKE) Standard

This tutorial shows you how to set up a single-replica WordPress deployment on Google Kubernetes Engine (GKE) using a MySQL database. Instead of installing MySQL, you use Cloud SQL, which provides a managed version of MySQL. WordPress uses PersistentVolumes (PV) and PersistentVolumeClaims (PVC) to store data.

Objectives

• Create a GKE cluster.
• Create a PV and a PVC backed by Persistent Disk.
• Create a Cloud SQL for MySQL instance.
• Deploy WordPress.
• Set up your WordPress blog.

Before you begin

1. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.
   Note: If you don’t plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.Go to project selector
2. Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.
3. In the console, activate Cloud Shell.Activate Cloud ShellAt the bottom of the console, a Cloud Shell session starts and displays a command-line prompt. Cloud Shell is a shell environment with the Google Cloud CLI already installed and with values already set for your current project. It can take a few seconds for the session to initialize.
4. In Cloud Shell, enable the GKE and Cloud SQL Admin APIs:gcloud services enable container.googleapis.com sqladmin.googleapis.com

Setting up your environment

1. In Cloud Shell, set the default zone for the Google Cloud CLI:gcloud config set compute/zone zone Replace the following:
   • zone: Choose a zone that’s closest to you. For more information, see Regions and Zones.
2. Set the PROJECT_ID environment variable to your Google Cloud project ID 
   (project-id).export PROJECT_ID=project-id
3. Download the app manifest files from the GitHub repository:
   git clone https://github.com/GoogleCloudPlatform/kubernetes-engine-samples
4. Change to the directory with the wordpress-persistent-disks file:
   cd kubernetes-engine-samples/wordpress-persistent-disks
5. Set the WORKING_DIR environment variable:
   WORKING_DIR=$(pwd)
For this tutorial, you create Kubernetes objects using manifest files in YAML format.

Creating a GKE cluster

You create a GKE cluster to host your WordPress app container.

• In Cloud Shell, create a cluster named persistent-disk-tutorial that has three nodes:CLUSTER_NAME=persistent-disk-tutorial
gcloud container clusters create $CLUSTER_NAME \
    --num-nodes=3 --enable-autoupgrade --no-enable-basic-auth \
    --no-issue-client-certificate --enable-ip-alias --metadata \
    disable-legacy-endpoints=true
Note: Ensure that you have properly set the zone as explained in this earlier step. If the zone is not set, gcloud will create a regional cluster. A regional cluster will create a node-pool of 3 nodes per zone within the default region for your project. This will result in a cluster with more nodes than a single zonal cluster, and possible quota issues.Creating a PV and a PVC backed by Persistent Disk

Create a PVC as the storage required for WordPress. GKE has a default StorageClass resource installed that lets you dynamically provision PVs backed by Persistent Disk. You use the wordpress-volumeclaim.yaml file to create the PVCs required for the deployment.

This manifest file describes a PVC that requests 200 GB of storage. A StorageClass resource hasn’t been defined in the file, so this PVC uses the default StorageClass resource to provision a PV backed by Persistent Disk.

1. In Cloud Shell, deploy the manifest file:
   kubectl apply -f $WORKING_DIR/wordpress-volumeclaim.yaml
It can take up to ten seconds to provision the PV backed by Persistent Disk and to bind it to your PVC. You can check the status with the following command:
   kubectl get persistentvolumeclaim
When the process is complete, an output similar to the following displays:
   NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE wordpress-volumeclaim Bound pvc-89d49350-3c44-11e8-80a6-42010a800002 200G RWO standard 5s

Creating a Cloud SQL for MySQL instance

1. In Cloud Shell, create an instance named mysql-wordpress-instance:
   INSTANCE_NAME=mysql-wordpress-instance
gcloud sql instances create $INSTANCE_NAME
2. Add the instance connection name as an environment variable:
   export INSTANCE_CONNECTION_NAME=$(gcloud sql instances describe $INSTANCE_NAME \
    --format='value(connectionName)')
3. Create a database for WordPress to store its data:
   gcloud sql databases create wordpress --instance $INSTANCE_NAME
4. Create a database user called wordpress and a password for WordPress to authenticate to the instance:
   CLOUD_SQL_PASSWORD=$(openssl rand -base64 18)
gcloud sql users create wordpress --host=% --instance $INSTANCE_NAME \
    --password $CLOUD_SQL_PASSWORD
If you close your Cloud Shell session, you lose the password. Make a note of the password because you need it later in the tutorial.

You have completed setting up the database for your new WordPress blog.

Deploying WordPress

Before you can deploy WordPress, you must create a service account. You create a Kubernetes secret to hold the service account credentials and another secret to hold the database credentials.

Configure a service account and create secrets

1. To let your WordPress app access the MySQL instance through a Cloud SQL proxy, create a service account:
   SA_NAME=cloudsql-proxy
gcloud iam service-accounts create $SA_NAME --display-name $SA_NAME
2. Add the service account email address as an environment variable:
   SA_EMAIL=$(gcloud iam service-accounts list \
    --filter=displayName:$SA_NAME \
    --format='value(email)')
3. Add the cloudsql.client role to your service account:
   gcloud projects add-iam-policy-binding $PROJECT_ID \
    --role roles/cloudsql.client \
    --member serviceAccount:$SA_EMAIL
4. Create a key for the service account:
   gcloud iam service-accounts keys create $WORKING_DIR/key.json \
    --iam-account $SA_EMAIL
This command downloads a copy of the key.json file.
5. Create a Kubernetes secret for the MySQL credentials:
   kubectl create secret generic cloudsql-db-credentials \
    --from-literal username=wordpress \
    --from-literal password=$CLOUD_SQL_PASSWORD
6. Create a Kubernetes secret for the service account credentials:
   kubectl create secret generic cloudsql-instance-credentials \
    --from-file $WORKING_DIR/key.json

Deploy WordPress

The next step is to deploy your WordPress container in the GKE cluster.

The wordpress_cloudsql.yaml manifest file describes a Deployment that creates a single Pod running a container with a WordPress instance. This container reads the WORDPRESS_DB_PASSWORD environment variable that contains the cloudsql-db-credentials secret you created.

This manifest file also configures the WordPress container to communicate with MySQL through the Cloud SQL proxy running in the sidecar container. The host address value is set on the WORDPRESS_DB_HOST environment variable.

1. Prepare the file by replacing the INSTANCE_CONNECTION_NAME environment variable:cat $WORKING_DIR/wordpress_cloudsql.yaml.template | envsubst > \
    $WORKING_DIR/wordpress_cloudsql.yaml
2. Deploy the wordpress_cloudsql.yaml manifest file:kubectl create -f $WORKING_DIR/wordpress_cloudsql.yaml
It takes a few minutes to deploy this manifest file while a Persistent Disk is attached to the compute node.
3. Watch the deployment to see the status change to running:kubectl get pod -l app=wordpress --watch
When the output shows the following status, you can move on to the next step.NAME READY STATUS RESTARTS AGE wordpress-387015-02xxb 2/2 Running 0 9h

Expose the WordPress service

In the previous step, you deployed a WordPress container, but it’s currently not accessible from outside your cluster because it doesn’t have an external IP address. You can expose your WordPress app to traffic from the internet by creating and configuring a Kubernetes Service with an attached external load balancer. To learn more about exposing apps using Services in GKE, see the how-to guide.

1. Create a Service of type:LoadBalancer:
   kubectl create -f $WORKING_DIR/wordpress-service.yaml
It takes a few minutes to create a load balancer.
2. Watch the deployment and wait for the service to have an external IP address assigned:
   kubectl get svc -l app=wordpress --watch
3. When the output shows an external IP address, you can proceed to the next step. Note that your external IP is different from the following example.
   NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE wordpress 10.51.243.233 203.0.113.3 80:32418/TCP 1m
4. Make a note of the EXTERNAL_IP address field to use later.

Warning: Don’t leave your WordPress installation with a load balancer that exposes the cluster. Other visitors can set up a website on your cluster and use it to serve potentially malicious content. Either continue with the installation steps or clean up this deployment.

Setting up your WordPress blog

In this section, you set up your WordPress blog.

1. In your browser, go to the following URL, replacing external-ip-address with the EXTERNAL_IP address of the service that exposes your WordPress instance:
   http://external-ip-address
2. On the WordPress installation page, select a language, and then click Continue.
3. Complete the Information needed page, and then click Install WordPress.
4. Click Log In.
5. Enter the username and password that you previously created.
6. You now have a blog site. To visit your blog, in your browser, go to the following URL:
   http://external-ip-address

Reference: https://cloud.google.com/kubernetes-engine/docs/tutorials/persistent-disk