Nginx as Load Balancer and Reverse Proxy for a Spring API

---

Table of Contents

• About
• Getting Started
• Generating SSL/TLS Certificate
• Usage

---

About

This project demonstrates how to configure Nginx as a load balancer and reverse proxy for a Spring Boot API running across three instances. It also covers how to enable HTTPS communication using a self-signed SSL certificate.

---

Getting Started

Prerequisites

• Docker Desktop

---

Generating SSL/TLS Certificate

To enable HTTPS, follow these steps to create a self-signed SSL certificate:

Steps

1. Open a terminal and navigate to the docker/ssl/ directory.

2. Run the following command:

   openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout nginx-selfsigned.key -out nginx-selfsigned.crt

This will generate a public/private key pair to establish secure HTTPS communication.

The certificate files will be automatically mounted into the Nginx container and referenced within the Nginx configuration file.

---

Running the Containers

Start the application using Docker Compose:

docker-compose up -d

---

Usage

Once the containers are running, open your browser or API tool (e.g., Postman) and access:

🔗 https://localhost:3443/api/greetings

How It Works

• localhost:3443 is mapped to the Nginx container.
• Docker maps this external port to internal port 443 (HTTPS).
• Nginx acts as a reverse proxy and load balancer, distributing requests among three Spring Boot instances.
• The /api/greetings endpoint returns a message indicating which instance handled the request.

---

📌 Note: Since the certificate is self-signed, your browser may display a security warning. You can proceed by accepting the risk manually.

---