What is the exact meaning of Docker?
Docker is a platform and toolset that allows you to develop, deploy, and run applications using containers. Containers are lightweight, portable, and self-sufficient units that encapsulate an application and its dependencies, including libraries, runtime, and environment variables. Docker provides a way to package and distribute applications in a consistent and isolated manner across different environments, from development to production.
Most applications involve more than one architectural component. In such applications, Docker-compose will help you run these components as defined in your application stack. It provides a single file that defines how different containers interact with each other as required by your application stack.
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
To deploy a WordPress image as a Docker container, follow these steps:
Step 1 – Install Docker
If you don’t have Docker installed, download and install it based on your operating system. You can find installation instructions on the official Docker website.
1. Update the package list:
sudo apt-get update2. Install the required packages:
sudo apt-get install ca-certificates curl gnupg lsb-release3. Create a directory for the Docker GPG key:
sudo mkdir -p /etc/apt/keyrings4. Add Docker’s GPG key:
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg5. 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/null6. Update Docker’s repository:
sudo apt-get update7. Finally, install the latest version of Docker Engine, containers, and Docker Compose.
sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin8. To confirm that the installation process was successful, run the following command. The following success message should appear:
sudo docker run hello-worldStep 2 – Set Up WordPress Container on Docker
In this tutorial, we will use the Docker compose method as it’s more straightforward and systematic. Docker Compose is a tool for defining and running multi-container Docker applications. It simplifies the management of multi-container setups like WordPress with its dependencies. Create a `docker-compose.yml` file in your project directory with the following content:
version: '3'
services:
db:
image: mysql:5.7
volumes:
- db_data:/var/lib/mysql
environment:
MYSQL_ROOT_PASSWORD: mysecretpassword
MYSQL_DATABASE: wordpressdb
wordpress:
image: wordpress:latest
ports:
- "8080:80"
volumes:
- wordpress_data:/var/www/html
environment:
WORDPRESS_DB_HOST: db
WORDPRESS_DB_NAME: wordpressdb
WORDPRESS_DB_USER: root
WORDPRESS_DB_PASSWORD: mysecretpassword
volumes:
db_data:
wordpress_data:
Save this file in your project directory.
Step 3 – Build the Project
Open a terminal and navigate to the directory where your docker-compose.yml file is located. Run the following command:
docker-compose up -dThis command will start the containers in the background. Docker Compose will create a network and named volumes for your data storage.
Step 4 – Access Your WordPress Installation
Open a web browser and navigate to http://localhost:8080. You should see the WordPress installation screen. Follow the on-screen instructions to set up your WordPress site.
Manage Your Containers
You can use the following commands to manage your Docker containers:
- To stop containers:
docker-compose down - To start containers:
docker-compose up -d - To view logs:
docker-compose logs
Customization and Plugins
You can customize your WordPress container by modifying the docker-compose.yml file or using environment variables. Additionally, you can add plugins, themes, and other modifications just as you would in a traditional WordPress environment.
Backing Up and Restoring Data
With Docker volumes, your data is stored outside the containers, making it easier to back up and restore. You can back up the volumes using various methods, such as creating snapshots or using backup tools.
Using Docker containers with WordPress can provide a consistent and isolated development environment, making it easier to collaborate, test, and deploy your websites. Just remember that while containers are great for development and staging, you should consider additional security and optimization measures for production deployments.
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.txtAs evident from the code, the WordPress database password is sourced from a file named wordpress_password.txt, which we have generated within the main directory.
Conclusion
Docker serves as an invaluable containerization tool that optimizes the development workflow, particularly for content management systems such as WordPress. Its lightweight environment ensures optimal utilization of system resources.
Throughout this guide, we’ve comprehensively grasped the Docker installation process on Ubuntu, macOS, and Windows platforms. Additionally, we’ve executed the deployment of WordPress containers on each of these operating systems. This guide delved into top-tier security practices with Docker secrets and illuminated the steps to transition your Docker-contained website onto a live production server.
I trust this tutorial has offered valuable insights. Should you have any queries or require further elucidation, we invite you to share your thoughts in the comments section below.
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