Master Nginx: From Basics to Advanced Configuration and Load Balancing

Nginx is a versatile web server that can act as a reverse proxy, load balancer, mail proxy, and HTTP cache, following a master‑slave architecture.

In simple terms, a web server is an intermediary: a client requests https://dev.to, the browser contacts the web server, which forwards the request to a backend server and returns the response.

Proxy and Reverse Proxy

Proxy : The client sends a request to a proxy server, which forwards it to the backend server; the backend server does not know which client originated the request.

Reverse Proxy

A reverse proxy works the opposite way: a client contacts the proxy (web server), which then selects one of multiple backend servers to handle the request.

Load Balancing

Load balancing is a specific use of reverse proxy that requires two or more backend servers; it distributes incoming requests across them using algorithms such as round‑robin.

Stateful vs Stateless Applications

Stateful application : Each backend server stores its own instance‑specific data, which can lead to inconsistent results when different clients are routed to different servers.

Stateless application : Clients receive a token from the web server; the token is sent with each request, allowing any backend server to produce the same output.

What Is Nginx?

Nginx acts as a middleman between clients and backend servers. In a typical setup, three backend servers run on ports 3001, 3002, and 3003, sharing a common database on port 5432.

Installation Process

On macOS you can install Nginx with Homebrew: $ brew install nginx After installation, start Nginx and verify it is running: $ nginx Open http://localhost:8080/ in a browser to see the default page.

Basic Configuration Settings and Example

Create the following directory structure:

.
├── nginx-demo
│  ├── content
│  │  ├── first.txt
│  │  ├── index.html
│  │  └── index.md
│  └── main
│    └── index.html
└── temp-nginx
   └── outsider
     └── index.html

Configure Nginx to serve the /content and /outsider URLs, block .md files, and set up a reverse‑proxy on port 8888:

http {
    server {
        listen 5000;
        root /path/to/nginx-demo/main/;
        location /content {
            root /path/to/nginx-demo/;
        }
        location /outsider {
            root /path/temp-nginx/;
        }
        location ~ .md {
            return 403;
        }
    }
    server {
        listen 8888;
        location / {
            proxy_pass http://localhost:5000/;
        }
        location /new {
            proxy_pass http://localhost:5000/outsider/;
        }
    }
    events {}
}

Run the configuration with:

sudo nginx

Additional Nginx Commands

Test configuration syntax: sudo nginx -T Reload a running server: nginx -s reload Stop the server: nginx -s stop Check running processes and terminate if needed:

ps -ef | grep nginx
kill -9 <PID>