How To Install WordPress With Docker Compose

by DigitalOcean

Introduction

WordPress is a free and open-source Content Management System (CMS) built on a MySQL database with PHP processing. Thanks to its extensible plugin architecture and templating system, and the fact that most of its administration can be done through the web interface, WordPress is a popular choice when creating different types of websites, from blogs to product pages to eCommerce sites.

Running WordPress typically involves installing a LAMP (Linux, Apache, MySQL, and PHP) or LEMP (Linux, Nginx, MySQL, and PHP) stack, which can be time-consuming. However, by using tools like Docker and Docker Compose, you can simplify the process of setting up your preferred stack and installing WordPress. Instead of installing individual components by hand, you can use images, which standardize things like libraries, configuration files, and environment variables, and run these images in containers, isolated processes that run on a shared operating system. Additionally, by using Compose, you can coordinate multiple containers — for example, an application and database — to communicate with one another.

In this tutorial, you will build a multi-container WordPress installation. Your containers will include a MySQL database, an Nginx web server, and WordPress itself. You will also secure your installation by obtaining TLS/SSL certificates with Let’s Encrypt for the domain you want associated with your site. Finally, you will set up a cron job to renew your certificates so that your domain remains secure.

Prerequisites

To follow this tutorial, you will need:

Step 1 — Defining the Web Server Configuration

Before running any containers, our first step will be to define the configuration for our Nginx web server. Our configuration file will include some WordPress-specific location blocks, along with a location block to direct Let’s Encrypt verification requests to the Certbot client for automated certificate renewals.

First, create a project directory for your WordPress setup called wordpress and navigate to it:

mkdir wordpress && cd wordpress

Next, make a directory for the configuration file:

mkdir nginx-conf

Open the file with nano or your favorite editor:

nano nginx-conf/nginx.conf

In this file, we will add a server block with directives for our server name and document root, and location blocks to direct the Certbot client’s request for certificates, PHP processing, and static asset requests.

Paste the following code into the file. Be sure to replace example.com with your own domain name:

~/wordpress/nginx-conf/nginx.conf
server {           listen 80;           listen [::]:80;              server_name example.com www.example.com;              index index.php index.html index.htm;              root /var/www/html;              location ~ /.well-known/acme-challenge {                   allow all;                   root /var/www/html;           }              location / {                   try_files $uri $uri/ /index.php$is_args$args;           }              location ~ .php$ {                   try_files $uri =404;                   fastcgi_split_path_info ^(.+.php)(/.+)$;                   fastcgi_pass wordpress:9000;                   fastcgi_index index.php;                   include fastcgi_params;                   fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;                   fastcgi_param PATH_INFO $fastcgi_path_info;           }              location ~ /.ht {                   deny all;           }              location = /favicon.ico {                    log_not_found off; access_log off;            }           location = /robots.txt {                    log_not_found off; access_log off; allow all;            }           location ~* .(css|gif|ico|jpeg|jpg|js|png)$ {                   expires max;                   log_not_found off;           }   }   

Our server block includes the following information:

Directives:

  • listen: This tells Nginx to listen on port 80, which will allow us to use Certbot’s webroot plugin for our certificate requests. Note that we are not including port 443 yet — we will update our configuration to include SSL once we have successfully obtained our certificates.
  • server_name: This defines your server name and the server block that should be used for requests to your server. Be sure to replace example.com in this line with your own domain name.
  • index: The index directive defines the files that will be used as indexes when processing requests to your server. We’ve modified the default order of priority here, moving index.php in front of index.html so that Nginx prioritizes files called index.php when possible.
  • root: Our root directive names the root directory for requests to our server. This directory, /var/www/html, is created as a mount point at build time by instructions in our WordPress Dockerfile. These Dockerfile instructions also ensure that the files from the WordPress release are mounted to this volume.

Location Blocks:

  • location ~ /.well-known/acme-challenge: This location block will handle requests to the .well-known directory, where Certbot will place a temporary file to validate that the DNS for our domain resolves to our server. With this configuration in place, we will be able to use Certbot’s webroot plugin to obtain certificates for our domain.
  • location /: In this location block, we’ll use a try_files directive to check for files that match individual URI requests. Instead of returning a 404 Not Found status as a default, however, we’ll pass control to WordPress’s index.php file with the request arguments.
  • location ~ .php$: This location block will handle PHP processing and proxy these requests to our wordpress container. Because our WordPress Docker image will be based on the php:fpm image, we will also include configuration options that are specific to the FastCGI protocol in this block. Nginx requires an independent PHP processor for PHP requests: in our case, these requests will be handled by the php-fpm processor that’s included with the php:fpm image. Additionally, this location block includes FastCGI-specific directives, variables, and options that will proxy requests to the WordPress application running in our wordpress container, set the preferred index for the parsed request URI, and parse URI requests.
  • location ~ /.ht: This block will handle .htaccess files since Nginx won’t serve them. The deny_all directive ensures that .htaccess files will never be served to users.
  • location = /favicon.ico, location = /robots.txt: These blocks ensure that requests to /favicon.ico and /robots.txt will not be logged.
  • location ~* .(css|gif|ico|jpeg|jpg|js|png)$: This block turns off logging for static asset requests and ensures that these assets are highly cacheable, as they are typically expensive to serve.

For more information about FastCGI proxying, see Understanding and Implementing FastCGI Proxying in Nginx. For information about server and location blocks, see Understanding Nginx Server and Location Block Selection Algorithms.

Save and close the file when you are finished editing. If you used nano, do so by pressing CTRL+X, Y, then ENTER.

With your Nginx configuration in place, you can move on to creating environment variables to pass to your application and database containers at runtime.

Step 2 — Defining Environment Variables

Your database and WordPress application containers will need access to certain environment variables at runtime in order for your application data to persist and be accessible to your application. These variables include both sensitive and non-sensitive information: sensitive values for your MySQL root password and application database user and password, and non-sensitive information for your application database name and host.

Rather than setting all of these values in our Docker Compose file — the main file that contains information about how our containers will run — we can set the sensitive values in an .env file and restrict its circulation. This will prevent these values from copying over to our project repositories and being exposed publicly.

In your main project directory, ~/wordpress, open a file called .env:

nano .env

The confidential values that we will set in this file include a password for our MySQL root user, and a username and password that WordPress will use to access the database.

Add the following variable names and values to the file. Remember to supply your own values here for each variable:

~/wordpress/.env
MYSQL_ROOT_PASSWORD=your_root_password   MYSQL_USER=your_wordpress_database_user   MYSQL_PASSWORD=your_wordpress_database_password   

We have included a password for the root administrative account, as well as our preferred username and password for our application database.

Save and close the file when you are finished editing.

Because your .env file contains sensitive information, you will want to ensure that it is included in your project’s .gitignore and .dockerignore files, which tell Git and Docker what files not to copy to your Git repositories and Docker images, respectively.

If you plan to work with Git for version control, initialize your current working directory as a repository with git init:

git init

Then open a .gitignore file:

nano .gitignore

Add .env to the file:

~/wordpress/.gitignore
.env   

Save and close the file when you are finished editing.

Likewise, it’s a good precaution to add .env to a .dockerignore file, so that it doesn’t end up on your containers when you are using this directory as your build context.

Open the file:

nano .dockerignore

Add .env to the file:

~/wordpress/.dockerignore
.env   

Below this, you can optionally add files and directories associated with your application’s development:

~/wordpress/.dockerignore
.env   .git   docker-compose.yml   .dockerignore   

Save and close the file when you are finished.

With your sensitive information in place, you can now move on to defining your services in a docker-compose.yml file.

Step 3 — Defining Services with Docker Compose

Your docker-compose.yml file will contain the service definitions for your setup. A service in Compose is a running container, and service definitions specify information about how each container will run.

Using Compose, you can define different services in order to run multi-container applications, since Compose allows you to link these services together with shared networks and volumes. This will be helpful for our current setup since we will create different containers for our database, WordPress application, and web server. We will also create a container to run the Certbot client in order to obtain certificates for our webserver.

To begin, open the docker-compose.yml file:

nano docker-compose.yml

Add the following code to define your Compose file version and db database service:

~/wordpress/docker-compose.yml
version: '3'      services:     db:       image: mysql:8.0       container_name: db       restart: unless-stopped       env_file: .env       environment:         - MYSQL_DATABASE=wordpress       volumes:          - dbdata:/var/lib/mysql       command: '--default-authentication-plugin=mysql_native_password'       networks:         - app-network   

The db service definition contains the following options:

  • image: This tells Compose what image to pull to create the container. We are pinning the mysql:8.0 image here to avoid future conflicts as the mysql:latest image continues to be updated. For more information about version pinning and avoiding dependency conflicts, see the Docker documentation on Dockerfile best practices.
  • container_name: This specifies a name for the container.
  • restart: This defines the container restart policy. The default is no, but we have set the container to restart unless it is stopped manually.
  • env_file: This option tells Compose that we would like to add environment variables from a file called .env, located in our build context. In this case, the build context is our current directory.
  • environment: This option allows you to add additional environment variables, beyond those defined in your .env file. We will set the MYSQL_DATABASE variable equal to wordpress to provide a name for our application database. Because this is non-sensitive information, we can include it directly in the docker-compose.yml file.
  • volumes: Here, we’re mounting a named volume called dbdata to the /var/lib/mysql directory on the container. This is the standard data directory for MySQL on most distributions.
  • command: This option specifies a command to override the default CMD instruction for the image. In our case, we will add an option to the Docker image’s standard mysqld command, which starts the MySQL server on the container. This option, --default-authentication-plugin=mysql_native_password, sets the --default-authentication-plugin system variable to mysql_native_password, specifying which authentication mechanism should govern new authentication requests to the server. Since PHP and therefore our WordPress image won’t support MySQL’s newer authentication default, we must make this adjustment in order to authenticate our application database user.
  • networks: This specifies that our application service will join the app-network network, which we will define at the bottom of the file.

Next, below your db service definition, add the definition for your wordpress application service:

~/wordpress/docker-compose.yml
...     wordpress:       depends_on:          - db       image: wordpress:5.1.1-fpm-alpine       container_name: wordpress       restart: unless-stopped       env_file: .env       environment:         - WORDPRESS_DB_HOST=db:3306         - WORDPRESS_DB_USER=$MYSQL_USER         - WORDPRESS_DB_PASSWORD=$MYSQL_PASSWORD         - WORDPRESS_DB_NAME=wordpress       volumes:         - wordpress:/var/www/html       networks:         - app-network   

In this service definition, we are naming our container and defining a restart policy, as we did with the db service. We’re also adding some options specific to this container:

  • depends_on: This option ensures that our containers will start in order of dependency, with the wordpress container starting after the db container. Our WordPress application relies on the existence of our application database and user, so expressing this order of dependency will enable our application to start properly.
  • image: For this setup, we are using the 5.1.1-fpm-alpine WordPress image. As discussed in Step 1, using this image ensures that our application will have the php-fpm processor that Nginx requires to handle PHP processing. This is also an alpine image, derived from the Alpine Linux project, which will help keep our overall image size down. For more information about the benefits and drawbacks of using alpine images and whether or not this makes sense for your application, see the full discussion under the Image Variants section of the Docker Hub WordPress image page.
  • env_file: Again, we specify that we want to pull values from our .env file, since this is where we defined our application database user and password.
  • environment: Here, we’re using the values we defined in our .env file, but we’re assigning them to the variable names that the WordPress image expects: WORDPRESS_DB_USER and WORDPRESS_DB_PASSWORD. We’re also defining a WORDPRESS_DB_HOST, which will be the MySQL server running on the db container that’s accessible on MySQL’s default port, 3306. Our WORDPRESS_DB_NAME will be the same value we specified in the MySQL service definition for our MYSQL_DATABASE: wordpress.
  • volumes: We are mounting a named volume called wordpress to the /var/www/html mountpoint created by the WordPress image. Using a named volume in this way will allow us to share our application code with other containers.
  • networks: We’re also adding the wordpress container to the app-network network.

Next, below the wordpress application service definition, add the following definition for your webserver Nginx service:

~/wordpress/docker-compose.yml
...     webserver:       depends_on:         - wordpress       image: nginx:1.15.12-alpine       container_name: webserver       restart: unless-stopped       ports:         - "80:80"       volumes:         - wordpress:/var/www/html         - ./nginx-conf:/etc/nginx/conf.d         - certbot-etc:/etc/letsencrypt       networks:         - app-network   

Again, we’re naming our container and making it dependent on the wordpress container in order of starting. We’re also using an alpine image — the 1.15.12-alpine Nginx image.

This service definition also includes the following options:

  • ports: This exposes port 80 to enable the configuration options we defined in our nginx.conf file in Step 1.
  • volumes: Here, we are defining a combination of named volumes and bind mounts:
    • wordpress:/var/www/html: This will mount our WordPress application code to the /var/www/html directory, the directory we set as the root in our Nginx server block.
    • ./nginx-conf:/etc/nginx/conf.d: This will bind mount the Nginx configuration directory on the host to the relevant directory on the container, ensuring that any changes we make to files on the host will be reflected in the container.
    • certbot-etc:/etc/letsencrypt: This will mount the relevant Let’s Encrypt certificates and keys for our domain to the appropriate directory on the container.

And again, we’ve added this container to the app-network network.

Finally, below your webserver definition, add your last service definition for the certbot service. Be sure to replace the email address and domain names listed here with your own information:

~/wordpress/docker-compose.yml
  certbot:       depends_on:         - webserver       image: certbot/certbot       container_name: certbot       volumes:         - certbot-etc:/etc/letsencrypt         - wordpress:/var/www/html       command: certonly --webroot --webroot-path=/var/www/html --email sammy@example.com --agree-tos --no-eff-email --staging -d example.com -d www.example.com   

This definition tells Compose to pull the certbot/certbot image from Docker Hub. It also uses named volumes to share resources with the Nginx container, including the domain certificates and key in certbot-etc and the application code in wordpress.

Again, we’ve used depends_on to specify that the certbot container should be started once the webserver service is running.

We’ve also included a command option that specifies a subcommand to run with the container’s default certbot command. The certonly subcommand will obtain a certificate with the following options:

  • --webroot: This tells Certbot to use the webroot plugin to place files in the webroot folder for authentication. This plugin depends on the HTTP-01 validation method, which uses an HTTP request to prove that Certbot can access resources from a server that responds to a given domain name.
  • --webroot-path: This specifies the path of the webroot directory.
  • --email: Your preferred email for registration and recovery.
  • --agree-tos: This specifies that you agree to ACME’s Subscriber Agreement.
  • --no-eff-email: This tells Certbot that you do not wish to share your email with the Electronic Frontier Foundation (EFF). Feel free to omit this if you would prefer.
  • --staging: This tells Certbot that you would like to use Let’s Encrypt’s staging environment to obtain test certificates. Using this option allows you to test your configuration options and avoid possible domain request limits. For more information about these limits, please see Let’s Encrypt’s rate limits documentation.
  • -d: This allows you to specify domain names you would like to apply to your request. In this case, we’ve included example.com and www.example.com. Be sure to replace these with your own domain.

Below the certbot service definition, add your network and volume definitions:

~/wordpress/docker-compose.yml
...   volumes:     certbot-etc:     wordpress:     dbdata:      networks:     app-network:       driver: bridge     

Our top-level volumes key defines the volumes certbot-etc, wordpress, and dbdata. When Docker creates volumes, the contents of the volume are stored in a directory on the host filesystem, /var/lib/docker/volumes/, that’s managed by Docker. The contents of each volume then get mounted from this directory to any container that uses the volume. In this way, it’s possible to share code and data between containers.

The user-defined bridge network app-network enables communication between our containers since they are on the same Docker daemon host. This streamlines traffic and communication within the application, as it opens all ports between containers on the same bridge network without exposing any ports to the outside world. Thus, our db, wordpress, and webserver containers can communicate with each other, and we only need to expose port 80 for front-end access to the application.

The finished docker-compose.yml file will look like this:

~/wordpress/docker-compose.yml
version: '3'      services:     db:       image: mysql:8.0       container_name: db       restart: unless-stopped       env_file: .env       environment:         - MYSQL_DATABASE=wordpress       volumes:          - dbdata:/var/lib/mysql       command: '--default-authentication-plugin=mysql_native_password'       networks:         - app-network        wordpress:       depends_on:          - db       image: wordpress:5.1.1-fpm-alpine       container_name: wordpress       restart: unless-stopped       env_file: .env       environment:         - WORDPRESS_DB_HOST=db:3306         - WORDPRESS_DB_USER=$MYSQL_USER         - WORDPRESS_DB_PASSWORD=$MYSQL_PASSWORD         - WORDPRESS_DB_NAME=wordpress       volumes:         - wordpress:/var/www/html       networks:         - app-network        webserver:       depends_on:         - wordpress       image: nginx:1.15.12-alpine       container_name: webserver       restart: unless-stopped       ports:         - "80:80"       volumes:         - wordpress:/var/www/html         - ./nginx-conf:/etc/nginx/conf.d         - certbot-etc:/etc/letsencrypt       networks:         - app-network        certbot:       depends_on:         - webserver       image: certbot/certbot       container_name: certbot       volumes:         - certbot-etc:/etc/letsencrypt         - wordpress:/var/www/html       command: certonly --webroot --webroot-path=/var/www/html --email sammy@example.com --agree-tos --no-eff-email --staging -d example.com -d www.example.com      volumes:     certbot-etc:     wordpress:     dbdata:      networks:     app-network:       driver: bridge     

Save and close the file when you are finished editing.

With your service definitions in place, you are ready to start the containers and test your certificate requests.

Step 4 — Obtaining SSL Certificates and Credentials

We can start our containers with the docker-compose up command, which will create and run our containers in the order we have specified. If our domain requests are successful, we will see the correct exit status in our output and the right certificates mounted in the /etc/letsencrypt/live folder on the webserver container.

Create the containers with docker-compose up and the -d flag, which will run the db, wordpress, and webserver containers in the background:

docker-compose up -d

You will see output confirming that your services have been created:

Output

Creating db ... done Creating wordpress ... done Creating webserver ... done Creating certbot ... done

Using docker-compose ps, check the status of your services:

docker-compose ps

If everything was successful, your db, wordpress, and webserver services will be Up and the certbot container will have exited with a 0 status message:

Output

Name Command State Ports ------------------------------------------------------------------------- certbot certbot certonly --webroot ... Exit 0 db docker-entrypoint.sh --def ... Up 3306/tcp, 33060/tcp webserver nginx -g daemon off; Up 0.0.0.0:80->80/tcp wordpress docker-entrypoint.sh php-fpm Up 9000/tcp

If you see anything other than Up in the State column for the db, wordpress, or webserver services, or an exit status other than 0 for the certbot container, be sure to check the service logs with the docker-compose logs command:

docker-compose logs service_name

You can now check that your certificates have been mounted to the webserver container with docker-compose exec:

docker-compose exec webserver ls -la /etc/letsencrypt/live

If your certificate requests were successful, you will see output like this:

Output

total 16 drwx------ 3 root root 4096 May 10 15:45 . drwxr-xr-x 9 root root 4096 May 10 15:45 .. -rw-r--r-- 1 root root 740 May 10 15:45 README drwxr-xr-x 2 root root 4096 May 10 15:45 example.com

Now that you know your request will be successful, you can edit the certbot service definition to remove the --staging flag.

Open docker-compose.yml:

nano docker-compose.yml

Find the section of the file with the certbot service definition, and replace the --staging flag in the command option with the --force-renewal flag, which will tell Certbot that you want to request a new certificate with the same domains as an existing certificate. The certbot service definition will now look like this:

~/wordpress/docker-compose.yml
...     certbot:       depends_on:         - webserver       image: certbot/certbot       container_name: certbot       volumes:         - certbot-etc:/etc/letsencrypt         - certbot-var:/var/lib/letsencrypt         - wordpress:/var/www/html       command: certonly --webroot --webroot-path=/var/www/html --email sammy@example.com --agree-tos --no-eff-email --force-renewal -d example.com -d www.example.com   ...   

You can now run docker-compose up to recreate the certbot container. We will also include the --no-deps option to tell Compose that it can skip starting the webserver service, since it is already running:

docker-compose up --force-recreate --no-deps certbot

You will see output indicating that your certificate request was successful:

Output

Recreating certbot ... done Attaching to certbot certbot | Saving debug log to /var/log/letsencrypt/letsencrypt.log certbot | Plugins selected: Authenticator webroot, Installer None certbot | Renewing an existing certificate certbot | Performing the following challenges: certbot | http-01 challenge for example.com certbot | http-01 challenge for www.example.com certbot | Using the webroot path /var/www/html for all unmatched domains. certbot | Waiting for verification... certbot | Cleaning up challenges certbot | IMPORTANT NOTES: certbot | - Congratulations! Your certificate and chain have been saved at: certbot | /etc/letsencrypt/live/example.com/fullchain.pem certbot | Your key file has been saved at: certbot | /etc/letsencrypt/live/example.com/privkey.pem certbot | Your cert will expire on 2019-08-08. To obtain a new or tweaked certbot | version of this certificate in the future, simply run certbot certbot | again. To non-interactively renew *all* of your certificates, run certbot | "certbot renew" certbot | - Your account credentials have been saved in your Certbot certbot | configuration directory at /etc/letsencrypt. You should make a certbot | secure backup of this folder now. This configuration directory will certbot | also contain certificates and private keys obtained by Certbot so certbot | making regular backups of this folder is ideal. certbot | - If you like Certbot, please consider supporting our work by: certbot | certbot | Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate certbot | Donating to EFF: https://eff.org/donate-le certbot | certbot exited with code 0

With your certificates in place, you can move on to modifying your Nginx configuration to include SSL.

Step 5 — Modifying the Web Server Configuration and Service Definition

Enabling SSL in our Nginx configuration will involve adding an HTTP redirect to HTTPS, specifying our SSL certificate and key locations, and adding security parameters and headers.

Since you are going to recreate the webserver service to include these additions, you can stop it now:

docker-compose stop webserver

Before we modify the configuration file itself, let’s first get the recommended Nginx security parameters from Certbot using curl:

curl -sSLo nginx-conf/options-ssl-nginx.conf https://raw.githubusercontent.com/certbot/certbot/master/certbot-nginx/certbot_nginx/options-ssl-nginx.conf

This command will save these parameters in a file called options-ssl-nginx.conf, located in the nginx-conf directory.

Next, remove the Nginx configuration file you created earlier:

rm nginx-conf/nginx.conf

Open another version of the file:

nano nginx-conf/nginx.conf

Add the following code to the file to redirect HTTP to HTTPS and to add SSL credentials, protocols, and security headers. Remember to replace example.com with your own domain:

~/wordpress/nginx-conf/nginx.conf
server {           listen 80;           listen [::]:80;              server_name example.com www.example.com;              location ~ /.well-known/acme-challenge {                   allow all;                   root /var/www/html;           }              location / {                   rewrite ^ https://$host$request_uri? permanent;           }   }      server {           listen 443 ssl http2;           listen [::]:443 ssl http2;           server_name example.com www.example.com;              index index.php index.html index.htm;              root /var/www/html;              server_tokens off;              ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;           ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;              include /etc/nginx/conf.d/options-ssl-nginx.conf;              add_header X-Frame-Options "SAMEORIGIN" always;           add_header X-XSS-Protection "1; mode=block" always;           add_header X-Content-Type-Options "nosniff" always;           add_header Referrer-Policy "no-referrer-when-downgrade" always;           add_header Content-Security-Policy "default-src * data: 'unsafe-eval' 'unsafe-inline'" always;           # add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;           # enable strict transport security only if you understand the implications              location / {                   try_files $uri $uri/ /index.php$is_args$args;           }              location ~ .php$ {                   try_files $uri =404;                   fastcgi_split_path_info ^(.+.php)(/.+)$;                   fastcgi_pass wordpress:9000;                   fastcgi_index index.php;                   include fastcgi_params;                   fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;                   fastcgi_param PATH_INFO $fastcgi_path_info;           }              location ~ /.ht {                   deny all;           }              location = /favicon.ico {                    log_not_found off; access_log off;            }           location = /robots.txt {                    log_not_found off; access_log off; allow all;            }           location ~* .(css|gif|ico|jpeg|jpg|js|png)$ {                   expires max;                   log_not_found off;           }   }   

The HTTP server block specifies the webroot for Certbot renewal requests to the .well-known/acme-challenge directory. It also includes a rewrite directive that directs HTTP requests to the root directory to HTTPS.

The HTTPS server block enables ssl and http2. To read more about how HTTP/2 iterates on HTTP protocols and the benefits it can have for website performance, please see the introduction to How To Set Up Nginx with HTTP/2 Support on Ubuntu 18.04.

This block also includes our SSL certificate and key locations, along with the recommended Certbot security parameters that we saved to nginx-conf/options-ssl-nginx.conf.

Additionally, we’ve included some security headers that will enable us to get A ratings on things like the SSL Labs and Security Headers server test sites. These headers include X-Frame-Options, X-Content-Type-Options, Referrer Policy, Content-Security-Policy, and X-XSS-Protection. The HTTP Strict Transport Security (HSTS) header is commented out — enable this only if you understand the implications and have assessed its “preload” functionality.

Our root and index directives are also located in this block, as are the rest of the WordPress-specific location blocks discussed in Step 1.

Once you have finished editing, save and close the file.

Before recreating the webserver service, you will need to add a 443 port mapping to your webserver service definition.

Open your docker-compose.yml file:

nano docker-compose.yml

In the webserver service definition, add the following port mapping:

~/wordpress/docker-compose.yml
...     webserver:       depends_on:         - wordpress       image: nginx:1.15.12-alpine       container_name: webserver       restart: unless-stopped       ports:         - "80:80"         - "443:443"       volumes:         - wordpress:/var/www/html         - ./nginx-conf:/etc/nginx/conf.d         - certbot-etc:/etc/letsencrypt       networks:         - app-network   

The docker-compose.yml file will look like this when finished:

~/wordpress/docker-compose.yml
version: '3'      services:     db:       image: mysql:8.0       container_name: db       restart: unless-stopped       env_file: .env       environment:         - MYSQL_DATABASE=wordpress       volumes:          - dbdata:/var/lib/mysql       command: '--default-authentication-plugin=mysql_native_password'       networks:         - app-network        wordpress:       depends_on:          - db       image: wordpress:5.1.1-fpm-alpine       container_name: wordpress       restart: unless-stopped       env_file: .env       environment:         - WORDPRESS_DB_HOST=db:3306         - WORDPRESS_DB_USER=$MYSQL_USER         - WORDPRESS_DB_PASSWORD=$MYSQL_PASSWORD         - WORDPRESS_DB_NAME=wordpress       volumes:         - wordpress:/var/www/html       networks:         - app-network        webserver:       depends_on:         - wordpress       image: nginx:1.15.12-alpine       container_name: webserver       restart: unless-stopped       ports:         - "80:80"         - "443:443"       volumes:         - wordpress:/var/www/html         - ./nginx-conf:/etc/nginx/conf.d         - certbot-etc:/etc/letsencrypt       networks:         - app-network        certbot:       depends_on:         - webserver       image: certbot/certbot       container_name: certbot       volumes:         - certbot-etc:/etc/letsencrypt         - wordpress:/var/www/html       command: certonly --webroot --webroot-path=/var/www/html --email sammy@example.com --agree-tos --no-eff-email --force-renewal -d example.com -d www.example.com      volumes:     certbot-etc:     wordpress:     dbdata:      networks:     app-network:       driver: bridge     

Save and close the file when you are finished editing.

Recreate the webserver service:

docker-compose up -d --force-recreate --no-deps webserver

Check your services with docker-compose ps:

docker-compose ps

You should see output indicating that your db, wordpress, and webserver services are running:

Output

Name Command State Ports ---------------------------------------------------------------------------------------------- certbot certbot certonly --webroot ... Exit 0 db docker-entrypoint.sh --def ... Up 3306/tcp, 33060/tcp webserver nginx -g daemon off; Up 0.0.0.0:443->443/tcp, 0.0.0.0:80->80/tcp wordpress docker-entrypoint.sh php-fpm Up 9000/tcp

With your containers running, you can now complete your WordPress installation through the web interface.

Step 6 — Completing the Installation Through the Web Interface

With our containers running, we can finish the installation through the WordPress web interface.

In your web browser, navigate to your server’s domain. Remember to substitute example.com here with your own domain name:

https://example.com   

Select the language you would like to use:

WordPress Language Selector

After clicking Continue, you will land on the main setup page, where you will need to pick a name for your site and a username. It’s a good idea to choose a memorable username here (rather than “admin”) and a strong password. You can use the password that WordPress generates automatically or create your own.

Finally, you will need to enter your email address and decide whether or not you want to discourage search engines from indexing your site:

WordPress Main Setup Page

Clicking on Install WordPress at the bottom of the page will take you to a login prompt:

WordPress Login Screen

Once logged in, you will have access to the WordPress administration dashboard:

WordPress Main Admin Dashboard

With your WordPress installation complete, you can now take steps to ensure that your SSL certificates will renew automatically.

Step 7 — Renewing Certificates

Let’s Encrypt certificates are valid for 90 days, so you will want to set up an automated renewal process to ensure that they do not lapse. One way to do this is to create a job with the cron scheduling utility. In this case, we will create a cron job to periodically run a script that will renew our certificates and reload our Nginx configuration.

First, open a script called ssl_renew.sh:

nano ssl_renew.sh

Add the following code to the script to renew your certificates and reload your web server configuration. Remember to replace the example username here with your own non-root username:

~/wordpress/ssl_renew.sh
#!/bin/bash      COMPOSE="/usr/local/bin/docker-compose --no-ansi"      cd /home/sammy/wordpress/   $COMPOSE run certbot renew --dry-run && $COMPOSE kill -s SIGHUP webserver   

This script first assigns the docker-compose binary to a variable called COMPOSE, and specifies the --no-ansi option, which will run docker-compose commands without ANSI control characters. It then changes to the ~/wordpress project directory and runs the following docker-compose commands:

  • docker-compose run: This will start a certbot container and override the command provided in our certbot service definition. Instead of using the certonly subcommand, we’re using the renew subcommand here, which will renew certificates that are close to expiring. We’ve included the --dry-run option here to test our script.
  • docker-compose kill: This will send a SIGHUP signal to the webserver container to reload the Nginx configuration. For more information on using this process to reload your Nginx configuration, please see this Docker blog post on deploying the official Nginx image with Docker.

Close the file when you are finished editing. Make it executable:

chmod +x ssl_renew.sh

Next, open your root crontab file to run the renewal script at a specified interval:

sudo crontab -e

If this is your first time editing this file, you will be asked to choose an editor:

Output

no crontab for root - using an empty one Select an editor. To change later, run 'select-editor'. 1. /bin/nano <---- easiest 2. /usr/bin/vim.basic 3. /usr/bin/vim.tiny 4. /bin/ed Choose 1-4 [1]: ...

At the bottom of the file, add the following line:

crontab
...   */5 * * * * /home/sammy/wordpress/ssl_renew.sh >> /var/log/cron.log 2>&1   

This will set the job interval to every five minutes, so you can test whether or not your renewal request has worked as intended. We have also created a log file, cron.log, to record relevant output from the job.

After five minutes, check cron.log to see whether or not the renewal request has succeeded:

tail -f /var/log/cron.log

You should see output confirming a successful renewal:

Output

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ** DRY RUN: simulating 'certbot renew' close to cert expiry ** (The test certificates below have not been saved.) Congratulations, all renewals succeeded. The following certs have been renewed: /etc/letsencrypt/live/example.com/fullchain.pem (success) ** DRY RUN: simulating 'certbot renew' close to cert expiry ** (The test certificates above have not been saved.) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

You can now modify the crontab file to set a daily interval. To run the script every day at noon, for example, you would modify the last line of the file to look like this:

crontab
...   0 12 * * * /home/sammy/wordpress/ssl_renew.sh >> /var/log/cron.log 2>&1   

You will also want to remove the --dry-run option from your ssl_renew.sh script:

~/wordpress/ssl_renew.sh
#!/bin/bash      COMPOSE="/usr/local/bin/docker-compose --no-ansi"      cd /home/sammy/wordpress/   $COMPOSE run certbot renew && $COMPOSE kill -s SIGHUP webserver   

Your cron job will ensure that your Let’s Encrypt certificates don’t lapse by renewing them when they are eligible. You can also set up log rotation with the Logrotate utility to rotate and compress your log files.

Conclusion

In this tutorial, you used Docker Compose to create a WordPress installation with an Nginx web server. As part of this workflow, you obtained TLS/SSL certificates for the domain you want associated with your WordPress site. Additionally, you created a cron job to renew these certificates when necessary.

As additional steps to improve site performance and redundancy, you can consult the following articles on delivering and backing up WordPress assets:

If you are interested in exploring a containerized workflow with Kubernetes, you can also check out:

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