Using WordPress with Docker containers

A WordPress stack running with Docker.

I will try to have separate containers for MySQL, PHP7-FPM and Nginx.

Overview

Create a bridge network for all the containers used by this project on your host.

docker network create -d bridge wordpress

Create a MySQL container with one database and database root user.

docker run -d --network=wordpress --env MYSQL_ROOT_PASSWORD=root --env MYSQL_DATABASE=wordpress --hostname=wordpress-db1 --name=wordpress-db1 mysql:5.7.17

Create an Nginx container mapping to a host directory containing the WordPress installation.

mkdir -p /home/alexis/mydocker/wordpress-project/wordpress

This project includes a couple of Nginx configuration files in its nginx directory but you can copy Nginx's default configuration files from a basic Nginx container. First create a basic Nginx container.

docker run -d --name=temp-nginx nginx:1.10.2 cd /my-nginx-conf docker cp temp-nginx:/etc/nginx/conf.d/default.conf /my-nginx-conf/conf.d/wordpress.conf docker cp temp-nginx:/etc/nginx/nginx.conf /my-nginx-conf/ docker rm -f temp-nginx

and then start a container to use those configuration files and easily reconfigure Nginx editing from the host.

docker run -d --network=wordpress -v /home/alexis/mydocker/dockerize-wordpress/nginx/conf.d/wordpress.conf:/etc/nginx/conf.d/wordpress.conf -v /home/alexis/mydocker/dockerize-wordpress/nginx/nginx.conf:/etc/nginx/nginx.conf -v /home/alexis/mydocker/wordpress-project/wordpress:/usr/share/nginx/html -p 40021:80 --hostname=wordpress-web1 --name=wordpress-web1 nginx:1.10.2

Create container for PHP FPM, which will be called from Nginx.:

docker run -d --network=wordpress -v /home/alexis/mydocker/wordpress-project/wordpress:/usr/share/nginx/html --hostname=wordpress-php1 --name=wordpress-php1 php:7.1.2-fpm

Manually add PHP extensions. This can be incorporated into my PHP Dockerfile later. See https://hub.docker.com/_/php/ for instructions.:

docker exec -it wordpress-php1 bash
apt-get update
apt-get install -y libfreetype6-dev libjpeg62-turbo-dev libmcrypt-dev libpng12-dev 
docker-php-ext-install -j$(nproc) iconv mcrypt
docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ && docker-php-ext-install -j$(nproc) gd
docker-php-ext-install -j$(nproc) pdo_mysql
docker-php-ext-install -j$(nproc) mysqli

Launch with Docker Compose.:

cd compose-wordpress
docker-compose up -d

Troubleshooting

If you get Call to undefined function mysql_connect() you may be missing mysqli to work with PHP 7.

The Nginx and PHP-FPM containers need to map to the same directory because Nginx only passes a path to PHP-FPM. If you get 404 errors visiting a php file you may need to verify that the SCRIPT_FILENAME parameter is passing the correct path. I temporarily changed the log_format main in nginx.conf to verify the value of $document_root and I noticed it was /etc/nginx/html so I added the root directive to the location block processing php files.:

location ~ \.php$ {
    try_files $uri =404;
    # root is super important to let the PHP-FPM access the path provided by Nginx
    root /usr/share/nginx/html;
    fastcgi_split_path_info ^(.+\.php)(/.+)$;
    # this points to the container running PHP-FPM
    fastcgi_pass wordpress-php1:9000;
    fastcgi_index index.php;
    include fastcgi_params;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    fastcgi_param PATH_INFO $fastcgi_path_info;
}