Building and Deploying a 3-Tier Application Using Docker & Docker Compose

🚀 Deploying a 3-Tier Application Using Docker and Docker Compose

Author: Palukuri Bhashwanth
Date: May 2025
Project: Bhashwanth-application (App Layer), bhashwanth-database (DB Layer)

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📌 Introduction

In this blog, I’ll walk you through how I containerized and deployed a 3-tier application using Docker and Docker Compose. The application consists of:

• Frontend/Backend (App Layer): Bhashwanth-application

• Database Layer: bhashwanth-database

• Reverse Proxy (Load Balancer): Nginx

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🧱 Architecture Overview

pgsqlCopyEdit           +---------------------+
           |     NGINX Proxy     |  (Load Balancer)
           +---------------------+
                     |
          -------------------------
          |                       |
+-------------------+   +----------------------+
| Bhashwanth-application |   | bhashwanth-database |
+-------------------+   +----------------------+
        (App)                    (MySQL/Postgres)

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⚙️ Technologies Used

• Docker

• Docker Compose

• NGINX (as reverse proxy)

• Python/Node.js for application (depending on use case)

• MySQL/PostgreSQL for the database

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📁 Project Structure

pgsqlCopyEditdockerwebapp/
│
├── bhashwanth-application/
│   ├── app.py / index.js
│   ├── requirements.txt / package.json
│   └── Dockerfile
│
├── bhashwanth-database/
│   └── init.sql
│
├── nginx/
│   └── default.conf
│
└── docker-compose.yml

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🐳 Dockerfile (for Bhashwanth-application)

Example for a Python Flask app:

DockerfileCopyEditFROM python:3.9-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
COPY . .
CMD ["python", "app.py"]

---

🐬 Docker Compose File: docker-compose.yml

yamlCopyEditversion: '3.8'

services:
  app:
    build: ./bhashwanth-application
    container_name: bhashwanth-app
    ports:
      - "5000:5000"
    depends_on:
      - db

  db:
    image: mysql:8.0
    container_name: bhashwanth-database
    environment:
      MYSQL_ROOT_PASSWORD: rootpass
      MYSQL_DATABASE: bhashwanthdb
      MYSQL_USER: bhashwanth
      MYSQL_PASSWORD: bhash123
    volumes:
      - db_data:/var/lib/mysql

  nginx:
    image: nginx:latest
    container_name: bhashwanth-nginx
    ports:
      - "80:80"
    volumes:
      - ./nginx/default.conf:/etc/nginx/conf.d/default.conf
    depends_on:
      - app

volumes:
  db_data:

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🧪 Running the Application

In your project root (dockerwebapp), simply run:

bashCopyEditdocker-compose up --build

To run in detached mode:

bashCopyEditdocker-compose up -d

Access the app via:

arduinoCopyEdithttp://localhost/

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✅ What I Learned

• How to set up a multi-container app using Docker Compose

• How to define service dependencies

• How to expose ports and use environment variables

• How to simulate production using NGINX reverse proxy

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🚀 Future Enhancements

• Add CI/CD pipeline using GitHub Actions or Jenkins

• Add logging and monitoring (ELK Stack / Prometheus + Grafana)

• Deploy to cloud platforms (AWS ECS, Azure App Service, etc.)

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📌 Conclusion

Containerizing and orchestrating a 3-tier application with Docker Compose makes development and deployment easier and more consistent. This hands-on project helped me grasp the end-to-end DevOps process using containers.