In this post, I would like to tell you how to deploy a simple WorldPress service with MySQL database in CoreOS cluster in 3 minutes. You may reference my previous blog to setup a CoreOS cluster locally if you don’t have one.

Ok, ssh to one of your cluster node, let’s start.

Step 1 Create MySQL service

Create a unit file mysql.service

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 [Unit]
Description=MySQL DataBase
After=etcd.service
After=docker.service

[Service]
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill mysql
ExecStartPre=-/usr/bin/docker rm mysql
ExecStartPre=/usr/bin/docker pull mysql:5.7
ExecStart=/usr/bin/docker run --name mysql -e MYSQL_ROOT_PASSWORD="wordpress" -e MYSQL_DATABASE="wordpress" -e MYSQL_USER="wordpress" -e MYSQL_PASSWORD="wordpress" mysql:5.7
ExecStop=/usr/bin/docker stop mysql

To start service, run

fleetctl start mysql.service

To view its status, (normally it should be active and running) run

fleetctl list-units

Step 2 Create WordPress service

Create the second unit file wordpress.service

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[Unit]
Description=WordPress
After=mysql.service

[Service]
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill wordpress
ExecStartPre=-/usr/bin/docker rm wordpress
ExecStartPre=/usr/bin/docker pull wordpress
ExecStart=/usr/bin/docker run --name wordpress --link mysql -p 8880:80 -e WORDPRESS_DB_PASSWORD=wordpress -e WORDPRESS_DB_NAME=wordpress -e WORDPRESS_DB_USER=wordpress wordpress
ExecStop=/usr/bin/docker stop wordpress

[X-Fleet]
X-ConditionMachineOf=mysql.service

Run

fleetctl start wordpress.service

Ok, it’s done! Go http://<your-coreos-host-ip>:8880 and you should see the WordPress install page.

WordPress Install Page

A bit Explanation

  • TimeoutStartSec=0 aims to turning off timeouts, as the docker pull may take a while
  • X-ConditionMachineOf=mysql.service means wordpress service runs on the same host with mysql service