- Install Docker Compose on Linux.
- Create a docker-compose.yml file to:
- Spin up 4 Apache HTTPD containers.
- Map ports 5000, 6000, 7000, and 8000.
- Serve unique welcome messages on each port using custom HTML files.
- Launch and verify the containers using Docker Compose.
- Understand how to manage the containers effectively.
- Download Docker Compose:
sudo curl -L "https://git.1-hub.cndocker/compose/releases/download/1.29.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
- Make it executable:
sudo chmod +x /usr/local/bin/docker-compose- Verify the installation:
docker-compose --versionIf installed correctly, it will display the version.
- Create a project directory and navigate into it:
mkdir my-docker-compose
cd my-docker-compose- Create custom HTML files: Each container will serve a unique welcome message.
<!DOCTYPE html>
<html>
<head><title>HPCSA</title></head>
<body><h1>Welcome to HPCSA</h1></body>
</html><!DOCTYPE html>
<html>
<head><title>DITISS</title></head>
<body><h1>Welcome to DITISS</h1></body>
</html><!DOCTYPE html>
<html>
<head><title>DAI</title></head>
<body><h1>Welcome to DAI</h1></body>
</html><!DOCTYPE html>
<html>
<head><title>ACTS</title></head>
<body><h1>Welcome to ACTS</h1></body>
</html>In the same directory, create docker-compose.yml with the following content:
version: '3'
services:
httpd5000:
image: httpd:latest
container_name: httpd5000
ports:
- "5000:80"
volumes:
- ./welcome_hpcsa.html:/usr/local/apache2/htdocs/index.html
networks:
- webnet
httpd6000:
image: httpd:latest
container_name: httpd6000
ports:
- "6000:80"
volumes:
- ./welcome_ditiss.html:/usr/local/apache2/htdocs/index.html
networks:
- webnet
httpd7000:
image: httpd:latest
container_name: httpd7000
ports:
- "7000:80"
volumes:
- ./welcome_dai.html:/usr/local/apache2/htdocs/index.html
networks:
- webnet
httpd8000:
image: httpd:latest
container_name: httpd8000
ports:
- "8000:80"
volumes:
- ./welcome_acts.html:/usr/local/apache2/htdocs/index.html
networks:
- webnet
networks:
webnet:
driver: bridge
-
Service Definition: The file defines four distinct services using the Apache HTTP server (httpd), each configured to serve different HTML content on specific ports. These services (httpd5000, httpd6000, httpd7000, and httpd8000) are isolated containers running the same base image (httpd:latest), but each one serves a unique HTML page.
-
Image and Container Naming: Each service uses the same httpd image, ensuring consistency in the environment setup. The container name for each service is explicitly defined (httpd5000, httpd6000, etc.), which helps with identification and management, especially when you are working with multiple containers
-
Port Mapping: The ports section maps the host machine’s ports to the container’s default Apache port (80). For instance, port 5000 on the host maps to port 80 inside the httpd5000 container. This exposes different web applications running in separate containers, each bound to a unique port for access.
-
Volume Mapping: The volumes section ensures that specific HTML files on the host system (e.g., ./welcome_hpcsa.html) are mounted into the container’s file system. The mapping directs these files to Apache’s default directory for serving HTML content (/usr/local/apache2/htdocs/index.html). This enables the serving of custom content without modifying the container's internal setup.
-
Networking Configuration: The containers are all connected to the same bridge network (webnet), allowing them to communicate with each other if needed. The use of a custom network provides network isolation from other containers or external systems, enhancing security and organization in a multi-container setup.
-
Network Driver: The bridge network driver is used, which is Docker's default for containers running in isolation. This creates a virtual private network for the containers, ensuring that they can communicate internally, but remain isolated from the external environment unless explicitly exposed through ports.
-
Scalability and Extensibility: This configuration is easy to scale. You could add more httpd services, adjust the volumes for different HTML content, or modify the ports to expand the deployment. This flexibility makes Docker Compose a powerful tool for managing containerized applications.
-
Separation of Concerns: By using separate containers for different services, the setup maintains logical isolation of the applications, which is crucial for troubleshooting, scalability, and maintaining clean separation between services, even if they are based on the same underlying technology (Apache HTTP server in this case).
In summary, this file outlines an advanced configuration for serving multiple web applications in an isolated, containerized environment. It leverages Docker's powerful networking and volume management features to ensure efficiency and flexibility in how web applications are served, all while maintaining simplicity and scalability.
Run the following command in the directory containing docker-compose.yml:
docker-compose up -dWhat happens when we do this ?
- Docker Compose will pull the httpd image (if not already available).
- Create and start 4 containers, each mapped to ports 5000, 6000, 7000, and 8000.
- Open the following URLs in your browser to test:
- http://localhost:5000 → Displays "Welcome to HPCSA".
- http://localhost:6000 → Displays "Welcome to DITISS".
- http://localhost:7000 → Displays "Welcome to DAI".
- http://localhost:8000 → Displays "Welcome to ACTS".
If you're using a remote server, replace localhost with the server's IP address.
To stop and remove the containers, use:
docker-compose down- Docker Compose Basics:
- How to define multiple services in a single YAML file.
- Port Mapping and Volume Binding:
- Map host ports to container ports and bind custom HTML files to serve specific
content.
- Efficient Container Management:
- Manage multiple containers simultaneously using docker-compose up and docker-
compose down.
You now know how to create and manage multiple containers with Docker Compose effectively. 🚀
👨💻 𝓒𝓻𝓪𝓯𝓽𝓮𝓭 𝓫𝔂: Suraj Kumar Choudhary | 📩 𝓕𝓮𝓮𝓵 𝓯𝓻𝓮𝓮 𝓽𝓸 𝓓𝓜 𝓯𝓸𝓻 𝓪𝓷𝔂 𝓱𝓮𝓵𝓹: csuraj982@gmail.com