This tutorial shows you how to set up a single-replica
Google Kubernetes Engine (GKE)
using a MySQL database. Instead of installing MySQL, you use
which provides a managed version of MySQL. WordPress uses
to store data.
A PV is a representation of storage volume in the cluster that is provisioned by an admin, or dynamically provisioned by Kubernetes, to fulfill a request made in a PVC. A PVC is a request for storage of a certain storage class by a user that can be fulfilled by a PV. PVs and PVCs are independent from Pod lifecycles and preserve data through restarting, rescheduling, and even deleting Pods. WordPress uses Persistent Disk as storage to back the PVs.
WordPress is a blogging tool that uses a relational database to store the blog articles and their related objects and metadata, and the local file system to store assets, such as pictures in a blog post. This tutorial uses the official WordPress Docker image from Docker Hub.
In general, a container's root file system isn't suitable to store persistent data. The containers you run on GKE are typically disposable entities, and the cluster manager can delete, evict, or reschedule any containers that become unavailable due to node failures or other causes. When nodes fail, all data saved to a container's root file system is lost.
Using PVs backed by Persistent Disk let you store your WordPress platform data outside the containers. This way, even if the containers are deleted, their data persists. With the default storage class, your Persistent Disk (and hence your data) doesn't move with your Pod if the Pod is rescheduled to another node. There are different ways to handle moving the data, but that's outside the scope of this tutorial. For more information, see Persistent volumes with Persistent Disk.
WordPress requires a PV to store data. For this tutorial, you use the default storage class to dynamically create a Persistent Disk and create a PVC for the deployment.
- 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.
This tutorial uses the following billable components of Google Cloud:
When you finish this tutorial, you can avoid continued billing by deleting the resources you created. For more information, see Cleaning up.
Before you begin
- Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
In the Google Cloud Console, on the project selector page, select or create a Google Cloud project.
Make sure that billing is enabled for your Cloud project. Learn how to confirm that billing is enabled for your project.
In the Cloud Console, activate Cloud Shell.
At the bottom of the Cloud Console, a Cloud Shell session starts and displays a command-line prompt. Cloud Shell is a shell environment with the Cloud SDK already installed, including the
gcloudcommand-line tool, and with values already set for your current project. It can take a few seconds for the session to initialize.
- In Cloud Shell, enable the GKE and
Cloud SQL Admin APIs:
gcloud services enable container.googleapis.com sqladmin.googleapis.com
Setting up your environment
In Cloud Shell, set the default zone for the
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.
PROJECT_IDenvironment variable to your Google Cloud project ID (project-id).
Download the app manifest files from the GitHub repository:
git clone https://github.com/GoogleCloudPlatform/kubernetes-engine-samples
Change to the directory with the
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-tutorialthat 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
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
PVs backed by Persistent Disk. You use the
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
StorageClass resource to provision a PV backed by Persistent Disk.
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
In Cloud Shell, create an instance named
INSTANCE_NAME=mysql-wordpress-instance gcloud sql instances create $INSTANCE_NAME
Add the instance connection name as an environment variable:
export INSTANCE_CONNECTION_NAME=$(gcloud sql instances describe $INSTANCE_NAME \ --format='value(connectionName)')
Create a database for WordPress to store its data:
gcloud sql databases create wordpress --instance $INSTANCE_NAME
Create a database user called
wordpressand a password for WordPress to authenticate to the instance:
CLOUD_SQL_PASSWORD=$(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.
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
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 $SA_NAME
Add the service account email address as an environment variable:
SA_EMAIL=$(gcloud iam service-accounts list \ --filter=displayName:$SA_NAME \ --format='value(email)')
cloudsql.clientrole to your service account:
gcloud projects add-iam-policy-binding $PROJECT_ID \ --role roles/cloudsql.client \ --member serviceAccount:$SA_EMAIL
Create a key for the service account:
gcloud iam service-accounts keys create $WORKING_DIR/key.json \ --iam-account $SA_EMAIL
This command downloads a copy of the
Create a Kubernetes secret for the MySQL credentials:
kubectl create secret generic cloudsql-db-credentials \ --from-literal username=wordpress \ --from-literal password=$CLOUD_SQL_PASSWORD
Create a Kubernetes secret for the service account credentials:
kubectl create secret generic cloudsql-instance-credentials \ --from-file $WORKING_DIR/key.json
The next step is to deploy your WordPress container in the GKE cluster.
wordpress_cloudsql.yaml manifest file describes a Deployment that creates
a single Pod running a container with a WordPress instance. This container
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
Prepare the file by replacing the
cat $WORKING_DIR/wordpress_cloudsql.yaml.template | envsubst > \ $WORKING_DIR/wordpress_cloudsql.yaml
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.
Watch the deployment to see the status change to
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.
Create a Service of
kubectl create -f $WORKING_DIR/wordpress-service.yaml
It takes a few minutes to create a load balancer.
Watch the deployment and wait for the service to have an external IP address assigned:
kubectl get svc -l app=wordpress --watch
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
Make a note of the
EXTERNAL_IPaddress field to use later.
Setting up your WordPress blog
In this section, you set up your WordPress blog.
In your browser, go to the following URL, replacing external-ip-address with the
EXTERNAL_IPaddress of the service that exposes your WordPress instance:
On the WordPress installation page, select a language, and then click Continue.
Complete the Information needed page, and then click Install WordPress.
Click Log In.
Enter the username and password that you previously created.
You now have a blog site. To visit your blog, in your browser, go to the following URL:
To avoid incurring charges to your Google Cloud account for the resources used in this tutorial, either delete the project that contains the resources, or keep the project and delete the individual resources.
Delete the project
- In the Cloud Console, go to the Manage resources page.
- In the project list, select the project that you want to delete, and then click Delete.
- In the dialog, type the project ID, and then click Shut down to delete the project.
Delete the individual resources
If you used an existing project and you don't want to delete it, delete the individual resources.
Delete the service:
kubectl delete service wordpress
Wait for the load balancer provisioned for the
wordpressService to be deleted. The load balancer is deleted asynchronously in the background.
Watch the deletion process:
watch gcloud compute forwarding-rules list
The load balancer is deleted when you see the following output:
Listed 0 items.
Delete the Deployment:
kubectl delete deployment wordpress
Delete the PVC for WordPress:
kubectl delete pvc wordpress-volumeclaim
This command also automatically deletes the PV and Persistent Disk.
Delete the GKE cluster:
gcloud container clusters delete $CLUSTER_NAME
Delete the Cloud SQL instance:
gcloud sql instances delete $INSTANCE_NAME
Remove the role from the service account:
gcloud projects remove-iam-policy-binding $PROJECT_ID \ --role roles/cloudsql.client \ --member serviceAccount:$SA_EMAIL
Delete the service account:
gcloud iam service-accounts delete $SA_EMAIL
- Using GKE to deploy apps with regional Persistent Disk.
- Configure a static IP and a domain name for your app.
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