Mastering Nginx: Essential Configuration, Reverse Proxy, and Load Balancing

Introduction

Nginx is a high‑performance HTTP and reverse‑proxy server created by Russian engineer Igor Sysoev, also supporting IMAP/POP3 and SMTP. Its strongest advantage is handling high concurrency and efficient load balancing, making it a popular Apache alternative for large sites such as Sina and Tencent.

Basic Features

Core Functions

Static‑file web server with open file‑descriptor caching

Reverse proxy with caching and load balancing

FastCGI support

Modular design (non‑DSO), gzip filter, SSI, image resizing

SSL support

Extended Functions

Name‑ and IP‑based virtual hosts

Keep‑alive connections

Graceful configuration reloads or version upgrades

Customizable access logs with log caching for performance

URL rewrite and alias support

IP‑ and user‑based authentication

Rate limiting and concurrent connection control

Architecture

A master process spawns one or more worker processes. Event‑driven mechanisms include kqueue, epoll, and /dev/poll, with message notifications via select, poll, or real‑time signals. Features such as sendfile, sendfile64, file AIO, and mmap are supported.

Module Types

Core modules

Standard HTTP modules

Optional HTTP modules

Mail modules

Third‑party extensions

Basic Configuration

Virtual‑host configuration is demonstrated, with many additional parameters available (see later sections).

Access Control

Access can be restricted based on users (using htpasswd files) and IP addresses.

Compression

Before sending responses, Nginx can enable gzip compression to save bandwidth and speed up client delivery. The default build includes gzip, which can be turned on directly.

Anti‑Hotlinking

Define allowed referrers and reject non‑compliant requests to prevent unauthorized linking of resources.

Reverse Proxy

Nginx implements reverse proxy via the proxy module. The key directive proxy_pass forwards a location’s URI to an upstream server or group, e.g., mapping /uri to /newuri on the upstream.

Caching

When acting as a reverse proxy, Nginx can cache upstream responses locally, allowing subsequent client requests for the same content to be served directly from the cache.

Load Balancing

The upstream module provides three load‑balancing algorithms: round‑robin, IP hash, and least connections.

Conclusion

This overview covered the fundamental Nginx configuration and usage. The author acknowledges the article may be somewhat disorganized for first‑time readers.