Master Nginx: Core Features, Use Cases, and Complete Configuration Guide

Nginx Overview

Nginx (pronounced “engine x”) is a high‑performance HTTP and reverse‑proxy web server that also provides IMAP/POP3/SMTP services. It is known for high performance, high concurrency, and low memory consumption, and is widely used in internet applications.

Key Features

High performance: event‑driven asynchronous non‑blocking processing.

High concurrency: can handle tens of thousands of simultaneous connections.

Low memory usage: consumes less memory than traditional web servers.

High stability: architecture ensures long‑term stable operation.

Rich modules: many modules to satisfy different needs.

Flexible configuration: concise syntax that is easy to understand.

Common Use Cases

Web server : serves static and dynamic pages, efficiently handling static resources such as images, CSS, JavaScript.

Reverse proxy : forwards client requests to multiple backend servers, hides real IP addresses and improves security.

Load balancer : distributes requests among backend servers to improve availability and performance.

Cache server : caches static resources to reduce backend load and speed up responses.

Static resource server : efficiently serves static files.

Load‑Balancing Algorithms

Round Robin : distributes requests sequentially to each server; simple but ignores server capacity differences.

Weighted Round Robin : assigns weights to servers and distributes requests proportionally; better utilizes resources.

Least Connections : sends request to the server with the fewest active connections; handles uneven load.

IP Hash : hashes client IP to consistently route the same client to the same server; enables session persistence.

Nginx Configuration Overview

The configuration file consists of several blocks:

main : global settings such as worker processes and log paths.

events : connection handling settings (e.g., epoll).

http : HTTP service settings, containing server and location blocks.

server : virtual host definitions (listen port, server_name, root, etc.).

location : URL matching and forwarding rules.

Common Directives

Global block worker_processes: number of worker processes (usually set to CPU cores). error_log: path and level of error logs. pid: path of the PID file. user: user and group for worker processes.

Events block worker_connections: maximum concurrent connections per worker. use: event model (e.g., epoll, kqueue).

http block include: include other configuration files. default_type: default MIME type. sendfile: enable efficient file transfer. keepalive_timeout: keep‑alive timeout. gzip: enable gzip compression.

server block listen: port and IP address. server_name: domain name. root: website root directory. index: default index file. access_log: access log path and format.

location block proxy_pass: forward request to backend. root: root directory for the location. index: default file for the location. rewrite: rewrite URL. return: return specific HTTP status or content.

Configuration Examples

Static file server:

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

Reverse‑proxy configuration:

server {
    listen 80;
    server_name api.example.com;
    location / {
        proxy_pass http://localhost:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

Load‑balancing configuration (least connections):

upstream backend_servers {
    least_conn;
    server 10.0.0.1;
    server 10.0.0.2;
}
server {
    listen 80;
    location / {
        proxy_pass http://backend_servers;
    }
}