What is NGINX? (2004)

Introduction to NGINX

NGINX (pronounced "engine-X") is a powerful and efficient web server and reverse proxy that handles HTTP requests. It serves as the first layer in a web application, sitting between clients (browsers) and backend servers, routing requests efficiently.

NGINX is commonly used for:

• Serving static content (HTML, images, CSS, JS).
• Reverse proxying (forwarding requests to backend servers).
• Load balancing (distributing requests across multiple servers).
• Caching (storing responses for faster delivery).
• Security enhancements (SSL termination, request filtering).

NGINX is optimized for handling multiple concurrent connections, making it a preferred choice for high-traffic websites and cloud-based applications.

What NGINX is NOT

1. HTML Processor – NGINX doesn’t process HTML; it forwards requests to backend servers (e.g., PHP, Node.js, or Python).
2. Database Query Handler – It does not directly fetch images, make API requests, or query databases.

Key Use Cases of NGINX

1. Processing HTTP Requests

NGINX efficiently processes and routes HTTP requests, ensuring optimal web performance.

2. Load Balancing

NGINX distributes incoming traffic across multiple servers to improve reliability and reduce downtime.
There are two primary load-balancing methods:

• Least Connections – Routes traffic to the server with the fewest active connections.
• Round Robin – Distributes requests sequentially among available servers.

3. Proxy Server

In environments with multiple backend servers, managing direct public access can be complex and risky. Instead, one NGINX server can act as the primary gateway, handling all requests and distributing them securely to backend servers.
Benefits of using NGINX as a proxy server:
✅ Enhanced Security – Hides backend servers from public access.
✅ Simplified Management – Centralized request routing.
✅ Load Balancing – Optimizes server resources.

4. Caching

NGINX stores cached responses, reducing server load and improving performance.

5. Data Compression & Streaming

NGINX compresses files before transmission and supports chunked video streaming to reduce bandwidth costs.

6. SSL/TLS Termination (Encryption & Decryption)

NGINX acts as an SSL/TLS terminator by handling encrypted HTTPS requests:

1. Receives encrypted HTTPS requests from clients.
2. Decrypts using its SSL certificate.
3. Processes the request (caching, routing, load balancing).
4. Re-encrypts (optional) before forwarding to backend servers.
5. Sends an encrypted response to the client.

NGINX Configuration

The main configuration file is nginx.conf, typically located at /etc/nginx/nginx.conf.

1. Serving Static Content

server {
    listen 80;
    server_name example.com www.example.com;
    
    location / {
        root /var/www/example.com;
        index index.html index.htm;
    }
}

2. Forwarding Traffic (Reverse Proxy)

server {
    listen 80;
    server_name example.com www.example.com;

    location / {
        proxy_pass http://backend-server-ip:port;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

3. SSL Configuration

server {
    listen 443 ssl;
    server_name example.com www.example.com;

    ssl_certificate /etc/nginx/ssl/cert.pem;
    ssl_certificate_key /etc/nginx/ssl/key.pem;
    
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers 'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384';
    
    location / {
        root /var/www/example.com;
        index index.html index.htm;
    }
}

4. Load Balancing Methods

Round Robin

upstream backend {
    server backend1.example.com;
    server backend2.example.com;
    server backend3.example.com;
}

server {
    listen 80;
    server_name lb.example.com;

    location / {
        proxy_pass http://backend;
    }
}

Least Connections

upstream backend {
    least_conn;
    server backend1.example.com;
    server backend2.example.com;
    server backend3.example.com;
}

5. Caching Configuration

http {
    proxy_cache_path /data/nginx/cache levels=1:2 keys_zone=my_cache:10m max_size=1g inactive=60m;

    server {
        listen 80;
        server_name example.com www.example.com;

        location / {
            proxy_pass http://backend-server-ip;
            proxy_cache my_cache;
            proxy_cache_valid 200 302 10m;
            proxy_cache_valid 404 1m;
        }
    }
}