How to Install WordPress on Docker (Windows, macOS, and Linux)

Setting up an isolated environment for developing WordPress websites can initially seem challenging. Luckily, containerization tools like Docker exist, which help to streamline the development, testing, and deployment processes.

This tutorial will show you how to install and deploy a local WordPress site on a Docker container. Additionally, we will touch on the best security and development practices for WordPress Docker containers.

What Exactly Is Docker?

Docker is an open-source containerization software that creates isolated environments to run various applications. Users can develop, test, and run multiple applications on the same physical and virtual servers.

Unlike virtual machines, each container does not require its own OS as it shares the host kernel. Thus, the machine’s workload is much more lightweight, and such a server can run multiple containers simultaneously without losing performance.

For example, Docker is highly useful for WordPress developers. A WordPress test environment usually uses up a lot of system resources, while Docker allows developers to make a minimal environment without wasting server space and memory.

How to Deploy WordPress Image as a Docker Container?

The following steps will show you how to install a WordPress content management system on a Docker container.

Step 1 – Install Docker

Docker is available for Windows, macOS, and Ubuntu. Here’s how you can install it on any of the three operating systems:

How to Install Docker on Ubuntu

In order to install Docker on a Linux VPS, you need to have a virtual private server (VPS) with one of the following operating systems:

• Ubuntu Jammy 22.04 (LTS)
• Ubuntu Impish 21.10
• Ubuntu Focal 20.04 (LTS)
• Ubuntu Bionic 18.04 (LTS)

Now, just follow the steps as shown:

1. Update the package list:

sudo apt-get update

2. Install the required packages:

sudo apt-get install ca-certificates curl gnupg lsb-release

3. Create a directory for the Docker GPG key:

sudo mkdir -p /etc/apt/keyrings

4. Add Docker’s GPG key:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg

5. Set up the repository:

echo \ "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \ $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

6. Update Docker’s repository:

sudo apt-get update

7. Lastly, install the latest version of Docker Engine, containerd, and Docker Compose.

sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin

8. To confirm that the installation process was successful, run the following command. The following success message should appear:

sudo docker run hello-world

How to Install Docker on macOS

In order to install Docker on a macOS machine, these requirements must be met:

• 4 GB of RAM
• macOS version 10.15 or newer
• No previous versions of VirtualBox 4.3.30 can be installed

Here’s how you can install Docker on macOS:

1. Download Docker for Mac and double-click the .dmg file you’ve saved. Then, drag and drop the Docker icon into your Applications folder.

You can find download links here:

• Mac with an Apple processor
• Mac with an Intel processor

2. Open your Applications folder and double-click docker.app. During the configuration process, you’ll be asked to enter your password.

3. When prompted, Accept the service agreement; otherwise, the installation will fail.

4. Once the installation process is finished, you should see the Docker menu on your desktop’s status bar.

How to Install Docker on Windows

In order to install Docker Desktop on a Windows machine, these requirements must be met:

• 4 GB of RAM
• 64-bit processor from 2010 or more recent
• Virtualization enabled in BIOS
• Linux kernel update package installed if you are using the WSL 2 Docker back-end

Here’s how you can install Docker on Windows 10 64-bit:

1. Enable Hyper-V on your system.
2. Download Docker Desktop for Windows and open the Docker for Windows Installer file.
3. In the Configuration dialog window, check the boxes based on your preferences. Click Ok.

4. Once the installation is finished, click Close and restart and wait for your computer to reboot.

5. After reboot, Accept the service agreement, and Docker will be ready to use.

Step 2 – Set Up WordPress Container on Docker

In order to set up WordPress on Docker, two methods are available ‒ the CLI and Docker compose. In this tutorial, we will use the Docker compose method as it’s more straightforward and systematic.

It’s worth noting that all required images are acquired from Docker Hub:

• WordPress – the official WordPress Docker image. Includes all WordPress files, Apache server, and PHP.
• MySQL – required for MySQL root user, password, and database connection variables.
• phpMyAdmin – a web application for managing databases.

1. Open your operating system’s preferred command line interface and check the Docker Compose Installation version:
   
   docker compose -version
   This will confirm that the Compose module is working correctly.
   
2. Create a new project directory for WordPress application with the following command:
   
   mkdir wordpress
   
3. Navigate to the new directory:
   
   cd wordpress
   
4. Using your preferred text editor, create a new docker-compose.yml file, and paste the contents below:

version: "3" 
# Defines which compose version to use
services:
  # Services line define which Docker images to run. In this case, it will be MySQL server and WordPress image.
  db:
    image: mysql:5.7
    # image: mysql:5.7 indicates the MySQL database container image from Docker Hub used in this installation.
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: MyR00tMySQLPa$$5w0rD
      MYSQL_DATABASE: MyWordPressDatabaseName
      MYSQL_USER: MyWordPressUser
      MYSQL_PASSWORD: Pa$$5w0rD
      # Previous four lines define the main variables needed for the MySQL container to work: database, database username, database user password, and the MySQL root password.
  wordpress:
    depends_on:
      - db
    image: wordpress:latest
    restart: always
    # Restart line controls the restart mode, meaning if the container stops running for any reason, it will restart the process immediately.
    ports:
      - "8000:80"
      # The previous line defines the port that the WordPress container will use. After successful installation, the full path will look like this: http://localhost:8000
    environment:
      WORDPRESS_DB_HOST: db:3306
      WORDPRESS_DB_USER: MyWordPressUser
      WORDPRESS_DB_PASSWORD: Pa$$5w0rD
      WORDPRESS_DB_NAME: MyWordPressDatabaseName
# Similar to MySQL image variables, the last four lines define the main variables needed for the WordPress container to work properly with the MySQL container.
    volumes:
      ["./:/var/www/html"]
volumes:
  mysql: {}

5. With the Docker Compose file created, run the following command in the same wordpress directory to create and start the containers:
   
   docker compose up -d

Step 3 – Complete WordPress Installation on a Web Browser

Open your browser and enter http://localhost:8000/. WordPress setup screen will appear. Select the preferred language and continue.

Fill in your site name, username, password, and email.

When a Success! message pops-up, log in using your newly created details.

Lastly, you’ll be presented with the main WordPress dashboard screen.

Setting up phpMyAdmin

phpMyAdmin is a great tool for viewing and managing any existing databases. All you need to do is include these lines to an existing .yml file just after the services line along with the MySQL database service:

version: "3"
services:
  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: MyR00tMySQLPa$$5w0rD
      MYSQL_DATABASE: MyWordPressDatabaseName
      MYSQL_USER: MyWordPressUser
      MYSQL_PASSWORD: Pa$$5w0rD
  phpmyadmin:
    image: phpmyadmin/phpmyadmin:latest
    restart: always
    environment:
      PMA_HOST: db
      PMA_USER: MyWordPressUser
      PMA_PASSWORD: Pa$$5w0rD
    ports:
      - "8080:80"

Save the file and run the docker-compose Docker command:

docker compose up -d

Once done, open http://localhost:8080/, and you’ll be able to see the phpMyAdmin interface along with your WordPress database.

How to Secure WordPress Installation With Docker Secrets

Sensitive data such as passwords, SSH keys, and other types of critical information should be treated with extra care. That is where Docker secrets come in. Users can use Docker secrets to manage sensitive data and securely transmit it to particular containers that need access to it only.

In this tutorial, we will use Docker secrets to mask our WORDPRESS_DB_PASSWORD variable. WordPress will get the database password from a secret file we shall provide ourselves. Here’s an example:

wordpress:
   depends_on:
     - db
   image: wordpress:latest
   restart: always
   ports:
   - "8000:80"
   environment:
     WORDPRESS_DB_HOST: db:3306
     WORDPRESS_DB_USER: MyWordPressUser
     WORDPRESS_DB_PASSWORD_FILE: /run/secrets/wordpress_password
     WORDPRESS_DB_NAME: MyWordPressDatabaseName
   secrets:
     - wordpress_password   
  
secrets:
 wordpress_password:
   file: ./wordpress_password.txt

As you can see, the WordPress database password is taken from a wordpress_password.txt file that we created in the same main directory.

Website Development on WordPress Docker Container

Docker also serves as an excellent development tool. It allows developers to run Docker Compose to quickly use WordPress instances in an isolated environment built with Docker containers.

For example, suppose a developer wants to test out a plugin or theme on some specific WordPress version. In that case, they can just edit the main YAML file to include the WordPress version they specifically need and test everything there.

Finding and manipulating files is also very straightforward. Whenever a user pulls an official WordPress image via Docker, it creates all the necessary files and folders, such as wp-content, wp-admin, and wp-includes. Thus, the whole development environment acts the same as a live WordPress website.

Docker also makes the process of sharing the development builds with your team simple and convenient, as all you need to do is create your own registry. Then the whole team will be able to share images with docker pull and docker push commands.

Conclusion

Docker is an excellent containerization tool to help streamline the development process for content management systems like WordPress. Its minimal environment enables you to maintain the efficiency of your system resources.

In this tutorial, we’ve learned how to install Docker on Ubuntu, macOS, and Windows and deploy a WordPress container for each of these operating systems. We’ve also covered the best security practices with Docker secrets and showed how to deploy your website from a Docker container to a live production server.

We hope this tutorial was helpful. If you have any further questions, don’t hesitate to share them in the comments section.