This tutorial shows you how to deploy a WordPress site and a MySQL database using Minikube. Both applications use PersistentVolumes and PersistentVolumeClaims to store data.
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 lifecycles and preserve data through restarting, rescheduling, and even deleting Pods.
kustomization.yaml
with kubectl apply -k ./
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:
To check the version, enterkubectl version
. The example shown on this page works with kubectl
1.14 and above. Download the following configuration files:
MySQL and Wordpress each require a PersistentVolume to store data. Their PersistentVolumeClaims will be created at the deployment step.
Many cluster environments have a default StorageClass installed. When a StorageClass is not specified in the PersistentVolumeClaim, the cluster's default StorageClass is used instead.
When a PersistentVolumeClaim is created, a PersistentVolume is dynamically provisioned based on the StorageClass configuration.
hostPath
provisioner. hostPath
volumes are only suitable for development and testing. With hostPath
volumes, your data lives in /tmp
on the node the Pod is scheduled onto and does not move between nodes. If a Pod dies and gets scheduled to another node in the cluster, or the node is rebooted, the data is lost. hostPath
provisioner, the --enable-hostpath-provisioner
flag must be set in the controller-manager
component. A Secret is an object that stores a piece of sensitive data like a password or key. Since 1.14, kubectl
supports the management of Kubernetes objects using a kustomization file. You can create a Secret by generators in kustomization.yaml
.
Add a Secret generator in kustomization.yaml
from the following command. You will need to replace YOUR_PASSWORD
with the password you want to use.
cat <<EOF >./kustomization.yaml
secretGenerator:
- name: mysql-pass
literals:
- password=YOUR_PASSWORD
EOF
The following manifest describes a single-instance MySQL Deployment. The MySQL container mounts the PersistentVolume at /var/lib/mysql. The MYSQL_ROOT_PASSWORD
environment variable sets the database password from the Secret.
application/wordpress/mysql-deployment.yaml
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
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
The following manifest describes a single-instance WordPress Deployment. The WordPress container mounts the PersistentVolume at /var/www/html
for website data files. The WORDPRESS_DB_HOST
environment variable sets the name of the MySQL Service defined above, and WordPress will access the database by Service. The WORDPRESS_DB_PASSWORD
environment variable sets the database password from the Secret kustomize generated.
application/wordpress/wordpress-deployment.yaml
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
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
Download the MySQL deployment configuration file.
curl -LO https://k8s.io/examples/application/wordpress/mysql-deployment.yaml
Download the WordPress configuration file.
curl -LO https://k8s.io/examples/application/wordpress/wordpress-deployment.yaml
Add them to kustomization.yaml
file.
cat <<EOF >>./kustomization.yaml
resources:
- mysql-deployment.yaml
- wordpress-deployment.yaml
EOF
The kustomization.yaml
contains all the resources for deploying a WordPress site and a MySQL database. You can apply the directory by
kubectl apply -k ./
Now you can verify that all objects exist.
Verify that the Secret exists by running the following command:
kubectl get secrets
The response should be like this:
NAME TYPE DATA AGE
mysql-pass-c57bb4t7mf Opaque 1 9s
Verify that a PersistentVolume got dynamically provisioned.
kubectl get pvc
The response should be like this:
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
mysql-pv-claim Bound pvc-8cbd7b2e-4044-11e9-b2bb-42010a800002 20Gi RWO standard 77s
wp-pv-claim Bound pvc-8cd0df54-4044-11e9-b2bb-42010a800002 20Gi RWO standard 77s
Verify that the Pod is running by running the following command:
kubectl get pods
RUNNING
. The response should be like this:
NAME READY STATUS RESTARTS AGE
wordpress-mysql-1894417608-x5dzt 1/1 Running 0 40s
Verify that the Service is running by running the following command:
kubectl get services wordpress
The response should be like this:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
wordpress LoadBalancer 10.0.0.89 <pending> 80:32406/TCP 4m
NodePort
. The EXTERNAL-IP is always pending. Run the following command to get the IP Address for the WordPress Service:
minikube service wordpress --url
The response should be like this:
http://1.2.3.4:32406
Copy the IP address, and load the page in your browser to view your site.
You should see the WordPress set up page similar to the following screenshot.
Run the following command to delete your Secret, Deployments, Services and PersistentVolumeClaims:
kubectl delete -k ./
© 2022 The Kubernetes Authors
Documentation Distributed under CC BY 4.0.
https://kubernetes.io/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/