192 lines
8.3 KiB
Markdown
192 lines
8.3 KiB
Markdown
---
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title: "Example: Deploying WordPress and MySQL with Persistent Volumes"
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assignees:
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- ahmetb
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---
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{% capture overview %}
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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.
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A [PersistentVolume](/docs/concepts/storage/persistent-volumes/) (PV) is a piece of storage in the cluster that has been provisioned by an administrator, and a [PeristentVolumeClaim](/docs/concepts/storage/persistent-volumes/#persistentvolumeclaims) (PVC) is a set amount of storage in a PV. PersistentVolumes and PeristentVolumeClaims are independent from Pod lifecycles and preserve data through restarting, rescheduling, and even deleting Pods.
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**Warning:** This deployment is not suitable for production use cases, as it uses single instance WordPress and MySQL Pods. Consider using [WordPress Helm Chart](https://github.com/kubernetes/charts/tree/master/stable/wordpress) to deploy WordPress in production.
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{: .warning}
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{% endcapture %}
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{% capture objectives %}
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* Create a PersistentVolume
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* Create a Secret
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* Deploy MySQL
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* Deploy WordPress
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* Clean up
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{% endcapture %}
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{% capture prerequisites %}
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{% include task-tutorial-prereqs.md %}
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Download the following configuration files:
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1. [local-volumes.yaml](/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/local-volumes.yaml)
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1. [mysql-deployment.yaml](/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/mysql-deployment.yaml)
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1. [wordpress-deployment.yaml](/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/wordpress-deployment.yaml)
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{% endcapture %}
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{% capture lessoncontent %}
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## Create a PersistentVolume
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MySQL and Wordpress each use a PersistentVolume to store data. While Kubernetes supports many different [types of PersistentVolumes](/docs/concepts/storage/persistent-volumes/#types-of-persistent-volumes), this tutorial covers [hostPath](/docs/concepts/storage/volumes/#hostpath).
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**Note:** If you have a Kubernetes cluster running on Google Container Engine, please follow [this guide](https://cloud.google.com/container-engine/docs/tutorials/persistent-disk).
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{: .note}
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### Setting up a hostPath Volume
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A `hostPath` mounts a file or directory from the host node’s filesystem into your Pod.
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**Warning:** Only use `hostPath` for developing and testing. With hostPath, your data lives 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, the data is lost.
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{: .warning}
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1. Launch a terminal window in the directory you downloaded the manifest files.
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2. Create two PersistentVolumes from the `local-volumes.yaml` file:
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kubectl create -f local-volumes.yaml
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{% include code.html language="yaml" file="mysql-wordpress-persistent-volume/local-volumes.yaml" ghlink="/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/local-volumes.yaml" %}
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{:start="3"}
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3. Run the following command to verify that two 20GiB PersistentVolumes are available:
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kubectl get pv
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The response should be like this:
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NAME CAPACITY ACCESSMODES RECLAIMPOLICY STATUS CLAIM STORAGECLASS REASON AGE
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local-pv-1 20Gi RWO Retain Available 1m
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local-pv-2 20Gi RWO Retain Available 1m
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## Create a Secret for MySQL Password
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A [Secret](/docs/concepts/configuration/secret/) is an object that stores a piece of sensitive data like a password or key. The manifest files are already configured to use a Secret, but you have to create your own Secret.
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1. Create the Secret object from the following command:
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kubectl create secret generic mysql-pass --from-literal=password=YOUR_PASSWORD
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**Note:** Replace `YOUR_PASSWORD` with the password you want to apply.
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{: .note}
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2. Verify that the Secret exists by running the following command:
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kubectl get secrets
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The response should be like this:
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NAME TYPE DATA AGE
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mysql-pass Opaque 1 42s
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**Note:** To protect the Secret from exposure, neither `get` nor `describe` show its contents.
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{: .note}
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## Deploy MySQL
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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.
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{% include code.html language="yaml" file="mysql-wordpress-persistent-volume/mysql-deployment.yaml" ghlink="/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/mysql-deployment.yaml" %}
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1. Deploy MySQL from the `mysql-deployment.yaml` file:
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kubectl create -f mysql-deployment.yaml
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2. Verify that the Pod is running by running the following command:
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kubectl get pods
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**Note:** It can take up to a few minutes for the Pod's Status to be `RUNNING`.
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{: .note}
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The response should be like this:
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NAME READY STATUS RESTARTS AGE
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wordpress-mysql-1894417608-x5dzt 1/1 Running 0 40s
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## Deploy WordPress
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The following manifest describes a single-instance WordPress Deployment and Service. It uses many of the same features like a PVC for persistent storage and a Secret for the password. But it also uses a different setting: `type: NodePort`. This setting exposes WordPress to traffic from outside of the cluster.
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{% include code.html language="yaml" file="mysql-wordpress-persistent-volume/wordpress-deployment.yaml" ghlink="/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/wordpress-deployment.yaml" %}
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1. Create a WordPress Service and Deployment from the `wordpress-deployment.yaml` file:
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kubectl create -f wordpress-deployment.yaml
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2. Verify that the Service is running by running the following command:
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kubectl get services wordpress
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The response should be like this:
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NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
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wordpress 10.0.0.89 <pending> 80:32406/TCP 4m
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**Note:** Minikube can only expose Services through `NodePort`. <br/><br/>The `EXTERNAL-IP` is always `<pending>`.
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{: .note}
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3. Run the following command to get the IP Address for the WordPress Service:
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minikube service wordpress --url
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The response should be like this:
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http://1.2.3.4:32406
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4. Copy the IP address, and load the page in your browser to view your site.
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You should see the WordPress set up page similar to the following screenshot.
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**Warning:** Do not leave your WordPress installation on this page. If another user finds it, they can set up a website on your instance and use it to serve malicious content. <br/><br/>Either install WordPress by creating a username and password or delete your instance.
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{: .warning}
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{% endcapture %}
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{% capture cleanup %}
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1. Run the following command to delete your Secret:
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kubectl delete secret mysql-pass
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2. Run the following commands to delete all Deployments and Services:
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kubectl delete deployment -l app=wordpress
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kubectl delete service -l app=wordpress
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3. Run the following commands to delete the PersistentVolumeClaims and the PersistentVolumes:
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kubectl delete pvc -l app=wordpress
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kubectl delete pv local-pv-1 local-pv-2
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**Note:** Any other Type of PersistentVolume would allow you to recreate the Deployments and Services at this point without losing data, but `hostPath` loses the data as soon as the Pod stops running.
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{: .note}
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{% endcapture %}
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{% capture whatsnext %}
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* Learn more about [Introspection and Debugging](/docs/tasks/debug-application-cluster/debug-application-introspection/)
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* Learn more about [Jobs](/docs/concepts/workloads/controllers/jobs-run-to-completion/)
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* Learn more about [Port Forwarding](/docs/tasks/access-application-cluster/port-forward-access-application-cluster/)
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* Learn how to [Get a Shell to a Container](/docs/tasks/debug-application-cluster/get-shell-running-container/)
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{% endcapture %}
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{% include templates/tutorial.md %}
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