WordPress in docker, the quickest setup to run WordPress

Using docker containers is a quick and (mostly) secure way to spin up a WordPress server. In this post, we will be using three services: WordPress, MySQL as database and NGINX as reverse proxy. All it needs is one file to compose the running containers and the NGINX configuration.
Lets get started!

How to configure the docker containers

We need to write to tell docker what services this project needs. This is done in the docker-compse.yml file.
Look at the code below and be surprised by how easy the setup is:

version: "3"
services:
  proxy: 
    image: nginx:latest
    container_name: production-nginx
    volumes:
      - /etc/letsencrypt/:/etc/letsencrypt/
      - ./nginx/:/etc/nginx/
    ports:
      - "80:80"
      - "443:443"
  wp:
    image: wordpress:latest
    restart: always
    container_name: production-wordpress
    environment:
      WORDPRESS_DB_HOST: production-db:3306
      WORDPRESS_DB_USER: dbuser
      WORDPRESS_DB_PASSWORD: dbpassword
      WORDPRESS_DB_NAME: wordpress
    volumes:
      - ./wordpress:/var/www/html
  db:
    image: mysql:5.7
    container_name: production-db
    restart: always
    environment:
      MYSQL_DATABASE: wordpress
      MYSQL_USER: dbuser
      MYSQL_PASSWORD: dbpassword
      MYSQL_RANDOM_ROOT_PASSWORD: "1"
    volumes:
      - ./mysql:/var/lib/mysql

As you can see, we need three containers to run WordPress in docker. WordPress itself, a MySQL database and NGINX for the reverse proxy.

Important to note are the volumes. We mount SSL certificates into the NGINX service and local folders as a volume into the WordPress and MySQL service. By doing this these services persist their data into a local folder instead of just having them in runtime memory and losing them when creating a new container.

How to configure NGINX

Once again, we start with a minimal nginx.conf example:

events {}
http {
  server_names_hash_bucket_size  64;
  error_log /etc/nginx/error_log.log debug;
  client_max_body_size 20m;
  proxy_cache_path /etc/nginx/cache keys_zone=one:500m max_size=1000m;

  # Redirect all http requests to https
  server {
    listen 80 default_server;
    listen [::]:80 default_server;
    server_name _;
    return 301 https://$host$request_uri;
  }

  # Redirect requests from https://www.example.com to https://example.com
  server {
    server_name www.example.com;
    listen 443 ssl;
    # Include SSL certificates managed by certbot
    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
    # Include letsencrypt standards
    include /etc/letsencrypt/options-ssl-nginx.conf;
    # Include proxy settings for docker/wordpress
    include /etc/nginx/includes/proxy.conf;
    # Use docker DNS for proxy resolving
    resolver 127.0.0.11;
    # https://www.example.com -> https://example.com
    rewrite ^/(.*) https://example.com/$1 permanent;
  }
  server {
    server_name example.com;
    listen 443 ssl;
    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
    include /etc/letsencrypt/options-ssl-nginx.conf;
    include /etc/nginx/includes/proxy.conf;
    resolver 127.0.0.11;

    index index.php;
    try_files $uri $uri/ =404;

    # This must match your container_name set in docker-compose.yml!
    set $wordpress http://production-wordpress;

    location / {
      proxy_set_header    X-Forwarded-Host   $host;
      proxy_set_header    X-Forwarded-Server $host;
      proxy_set_header    X-Forwarded-For    $proxy_add_x_forwarded_for;
      proxy_set_header    X-Real-IP          $remote_addr;
      proxy_set_header    Host               $host;
      proxy_set_header    X-Forwarded-Proto https;
      proxy_pass $wordpress;
    }
  }
}

Notable are the caching options that should work well for you as well, the SSL configuration which requires a working certificate (I manage mine through certbot, I might write another post about that), the docker-internal proxy resolver at 127.0.0.11 which allows us to use container names as valid hostnames and the proxy_set_header configuration in our main location block.

These settings above are the absolute minimum to get this example to work. I recommend you to have a look at the way sites-available and sites-enabled work. You can put server blocks into their own files this way, which keeps your nginx.conf clean when you run multiple virtual server blocks.
Also be sure to replace example.com with your domain.

Running WordPress in docker

As everything is configured now (yes, really, we don’t need to configure anything for WordPress or MySQL) we can start the whole unit with docker-compose up -d, which will pull all images for the containers, create the services, start them and detach from their output.

Normally you should see everything starting, the last lines would be something around

[...]
Starting production-nginx     ... done
Starting production-wordpress ... done
Starting production-db        ... done

But if you run into any errors you should check the logs of the service with docker-compose logs and the content of nginx/error_log.log which will hold a lot of important informations about your proxy setup.

You might also get errors because of your SSL certificates/Lets Encrypt – I really recommend to setup these over certbot. Interrested in learning how? Leave a comment and I’ll write a post for this.

If everything went fine – nice! Check your domain to see the WordPress initalization setup and leave a comment that everything worked.

If it doesn’t do be shy to contact me using the contact page.