🐳 Docker Networking - Microservices Application

🎯 Overview A 3-tier microservices application demonstrating Docker networking, service discovery, and container orchestration using Docker Compose.

Architecture:

Browser → Frontend (Nginx :8080) ↓ Frontend → Backend (Node.js :3000) ↓ Backend → Database (MySQL :3306)

🏗️ Architecture Diagram

+------------------+ +------------------+ +------------------+ | Frontend | ---> | Backend | ---> | Database | | (Nginx :8080) | | (Node.js :3000) | | (MySQL :3306) | +------------------+ +------------------+ +------------------+ ___________________________________________/ myapp-network (bridge)

🛠️ Tech Stack

Component	Technology	Version
Frontend	Nginx	Alpine
Backend	Node.js + Express	18-alpine
Database	MySQL	8.0
Orchestration	Docker Compose	3.8

⚙️ Prerequisites

• Docker Desktop 4.0+
• Docker Compose 2.0+
• 2GB RAM minimum
• Ports 8080 and 3000 available

Check installation:

docker --version docker-compose --version

🚀 Quick Start

Clone repository

git clone https://github.com/kaelcloud/Docker-Networking.git cd docker-networking

Build & run containers

docker-compose up -d --build

Access:

• Frontend → http://localhost:8080
• Backend → http://localhost:3000/health

📂 Project Structure

docker-networking/ ├── docker-compose.yml ├── backend/ │ ├── Dockerfile │ ├── package.json │ └── server.js ├── frontend/ │ ├── Dockerfile │ └── index.html └── database/ └── init.sql

🔌 API Endpoints

Method	Endpoint	Description
GET	/health	Health check
GET	/api/users	Get all users
GET	/api/users/:id	Get user by ID

Example:

curl http://localhost:3000/api/users

🧪 Testing

Health check

curl http://localhost:3000/health

Check containers

docker-compose ps

Enter backend & ping database

docker exec -it backend sh ping database exit

🧱 Database Schema

sql CREATE TABLE users ( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100), role VARCHAR(100) );

Sample Data: Ahmad (DevOps), Siti (SysEng), Ali (Backend), Fatimah (Frontend), Kumar (DBA)

🩺 Troubleshooting (Quick Fix)

Port in Use:
→ Change exposed ports in docker-compose.yml or stop conflicting containers.

Backend can’t reach DB:
→ Run docker-compose logs backend, ensure DB is healthy.

DB not ready:
→ Wait for DB health check → docker-compose ps.

💡 What I Learned

• Docker custom bridge networks
• Service discovery via container names
• Multi-container orchestration
• Persistent volumes
• Health checks & dependencies
• Network isolation & security best practices

🚀 Next Steps

• Add authentication & HTTPS
• Implement CI/CD pipeline
• Add monitoring (Prometheus/Grafana)
• Deploy to Kubernetes

👤 Author Muhammad Hazran Hafiz bin Ahmad
GitHub: @kaelcloud
LinkedIn: [Muhammad Hazran Hafiz]