Docker Cookbook

7.1 Using Docker Compose to Create a WordPress Site
Problem
You have created a WordPress site using 
Recipe 1.16
, but you would like to describe
the multicontainer setup in a clear manifest and bring up the containers in a single
command.
Solution
Use Docker 
Compose
, a command-line utility to define and run multicontainer
applications with Docker. With Compose, you define the services that need to run in
a YAML file. Then bring up the services by using the 
docker-compose
command.
The first thing to do is to 
install
 Compose. You can install it via the Python index or
via a single 
curl
command.
If you are starting on your own Docker host, install Compose manually via the
Python package index using 
pip
:
$ sudo apt-get install python-pip
$ sudo pip install -U docker-compose
Or via 
curl
:
194 | Chapter 7: The Docker Ecosystem: Tools

---

$ curl -L https://github.com/docker/compose/releases/download/1.4.0/\
docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose
If you are using my examples, you are just a 
vagrant up
away from using Compose:
$ git clone https://github.com/how2dock/docbook.git
$ cd docbook/ch07/compose/
$ vagrant up
$ vagrant ssh
$ docker-compose --version
docker-compose 1.4.0
The next step is to define the two containers that compose your WordPress installa‐
tion in a YAML file. Each service will run via a container. You give them a name. In
this case, you will call the WordPress service 
wordpress
and the MySQL service 
db
.
Each service will then be defined by an image. The various arguments given at the
command line in 
Recipe 1.16
 need to be set in this YAML config file: the exposed
ports, the environment variables, and the mounted volumes.
Create the following 
docker-compose.yml
text file (if you are using my Vagrant
machine, the file is already in 
/vagrant/docker-compose.yml
):
wordpress:
image: wordpress
links:
- mysql
ports:
- 
"80:80"
environment:
- WORDPRESS_DB_NAME=wordpress
- WORDPRESS_DB_USER=wordpress
- WORDPRESS_DB_PASSWORD=wordpresspwd
mysql:
image: mysql
volumes:
- /home/docker/mysql:/var/lib/mysql
environment:
- MYSQL_ROOT_PASSWORD=wordpressdocker
- MYSQL_DATABASE=wordpress
- MYSQL_USER=wordpress
- MYSQL_PASSWORD=wordpresspwd
To bring up the two containers, type 
docker-compose up -d
at the command line, in
the directory where you have your 
docker-compose.yml
file. The two linked containers
will start, and you will be able to access the WordPress site by opening your browser
at 
http://
:
$ docker-compose up -d
Creating vagrant_mysql_1...
Creating vagrant_wordpress_1...
$ docker-compose ps
Name Command State Ports