NGINX as a Load Balancer with Dockerized Backend Apps

This project demonstrates how NGINX can be used as a reverse proxy and load balancer to distribute traffic across multiple backend services running in Docker containers. It includes SSL setup, HTTPS redirection, and load balancing using the least connections algorithm.

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📌 Project Highlights

• HTTPS with self-signed certificates
• Reverse proxy and routing using NGINX
• Load balancing across 3 app instances
• Docker Compose setup for backend services
• Basic CI-ready structure

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Docker Compose Setup

Here is the Docker Compose file used to run three backend instances of the same app on different ports. Each app responds with its name to help visualize load balancing.

version: '3'
services:
  app1:
    build: .
    environment:
      - APP_NAME=App1
    ports:
      - "3001:3000"

  app2:
    build: .
    environment:
      - APP_NAME=App2
    ports:
      - "3002:3000"

  app3:
    build: .
    environment:
      - APP_NAME=App3
    ports:
      - "3003:3000"

NGINX Configuration

upstream nodejs_cluster {
    least_conn;
    server 192.168.56.11:3001;
    server 192.168.56.11:3002;
    server 192.168.56.11:3003;
}

server {
    listen 443 ssl;
    server_name 192.168.56.11;

    ssl_certificate /path/to/cert.crt;
    ssl_certificate_key /path/to/key.key;

    location / {
        proxy_pass http://nodejs_cluster;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

server {
    listen 8080;
    location / {
        return 301 https://$host$request_uri;
    }
}

start and stop nginx server

sytemctl start nginx
systemctl enable nginx
systemctl status nginx
systemctl restart nginx
systemctl stop nginx

print logs

 tail -f /usr/local/var/log/nginx/access.log

create folder for nginx certificates

mkdir ~/nginx-certs
cd ~/nginx-certs

create self-signed certificate

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