Deploy Wordpress on Docker using Ansible

Overview

The following article will cover the steps how to deploy Wordpress on Docker using Ansible. Purpose of this procedure is to automatize the deployment process of Wordpress on Docker with the Ansible playbook.

In order to deploy wordpress on docker using ansible successfully, there are some requirements first to configure(listed bellow in the prerequisites)

Prerequisites

Docker installed and running on the target host machine(Docker installation can also be automated with Ansible – link to the POST)
SSH access enabled on the remote hosts with the login parameters preset in the Ansible hosts file
Ansible installed on client machine(your machine)
Installed Python and Python docker module for Ansible on target machine
Installed Python on your local machine

Install Python Docker module for Ansible

Most Linux distros have Python3 preinstalled but for others the Python Docker module that Ansible uses may be missing. You’ll know that it’s if you get an error mentioning that the module is missing or not found. Picture example of the error bellow:

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The mentioned module is actually the Docker SDK that Python uses to work with Docker. The easiest way to install the Python Docker module is with the “pip” tool. If the “pip” tool is missing, you can easily install and then with it to install the python docker module:

Debian/Ubuntu

sudo apt install python3-pip

Fedora

sudo dnf install python3-pip

CentOS/RedHat

sudo yum python3-pip

After you installed the pip, then run the command to install docker module:

pip3 install docker

If by any chance, you encounter an error in Ansible that the it cannot find the Python module, add a python interpreter variable in your hosts file. In most cases it’s located either in “/usr/bin/python3” or “/usr/lib/python3”.

Error looks something like this:

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The interpreter variable in the hosts file looks something like this:

ansible_python_interpreter=/usr/bin/python3

First step – Adding the necessary parameters in hosts file so that the Ansible can reach, login and interact with our machine:

sudo nano /etc/ansible/hosts

In the hosts file, add the parameters to look something like this:

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After the necessary parameters for our remote host are added, save the file and exit.

Ansible playbook for Wordpress deployment on Docker

For this deployment, we’ll be using the following playbook:

---
- hosts: docker
    vars:
      db_volume: mariadb
      wordpress: wordpress
    tasks:
      - name: Deploy MariaDB server
        docker_container:
          image: mariadb
          name: mariadb
          volumes:
            - "{{db_volume}}:/var/lib/mysql"
          env:
            MYSQL_ROOT_PASSWORD: somerootpassword
            MYSQL_PASSWORD: somemysqlpassword
            MYSQL_DATABASE: db
            MYSQL_USER: mysqluser

      - name: Deploy Wordpress
        docker_container:
          image: wordpress
          name: wordpress
          restart_policy: always
          ports:
            - "8080:80"
          links:
            - "{{db_volume}}:/var/lib/mysql"
          volumes:
            - "{{wordpress}}:/var/www/html"
          env:
            MYSQL_PASSWORD: somemysqlpassword
            MYSQL_DATABASE: db
            MYSQL_USER: mysqluser
            MYSQL_HOST: mariadb

[ Deploy Wordpress on Docker using Ansible ]

Feel free to just copy it.

Playbook breakdown:

hosts: docker // variable to target only machine hosts that are in the docker group

vars:

db_volume: mariadb

wordpress: wordpress  // [OPTIONAL] defined variables for each container. These are used for setting volumes on the host and are matching the container names.

tasks: // Defined a task which will deploy a MariaDB container(MariaDB database server in container form). Task will pull down the official Docker image of MariaDB from the Docker hub, set a name container name "mariadb" and set a persistent volume on the host machine for the database storage.

- name: Deploy MariaDB server // Task name

docker_container: // Docker function that Ansible will use

image: mariadb  // Docker image to pull down

name: mariadb // Specify the container name

volumes: - "{{db_volume}}:/var/lib/mysql" // Specify a volume on the host machine for persistent storage

env: // Environment variables to define parameters for the database such as the root password, admin user password, name of the database and the user name of the new user on the MariaDB server

MYSQL_ROOT_PASSWORD: somerootpassword // MySQL root password

MYSQL_PASSWORD: somemysqlpassword // MySQL admin/standard user password to be used by Wordpress

MYSQL_DATABASE: db // MySQL database name

MYSQL_USER: mysqluser // Admin/standard user username for Wordpress to use

// This the task that will deploy the Wordpress Docker container. Same just like for the MariaDB container, Ansible will pull down the official Wordpress image from the Docker hub. Here we also specified the container restart policy(when to restart the container) and also set number of ports to expose on the container and bind to the host, so that the container can be accessible via browser and http protocol. 

- name: Deploy Wordpress // Task name

docker_container: // Docker function that Ansible will use

image: wordpress // Docker image to pull down

name: wordpress // Specify the container name

restart_policy: always // Set attribute for container restart

ports: - "8080:80" // Specify ports to expose on the container to be accessible via web browser 

links:
- "{{db_volume}}:/var/lib/mysql // Variable to specify the link to the MySQL server so that Wordpress can connect to the database

volumes: - "{{wordpress}}:/var/www/html" // Specify a volume on the host machine for persistent storage

// Environment variables for the MariaDB database, for Wordpress to use in order to connect to the database and use the database for data storage. 

env: 

MYSQL_PASSWORD: somemysqlpassword // Variable to specify MySQL for Wordpress to use

MYSQL_DATABASE: db // MySQL database name which will Wordpress connect to 

MYSQL_USER: mysqluser // MySQL user for Wordpress to use

MYSQL_HOST: mariadb // MySQL database server to connect to(docker container name we previously set)