Master Nginx: From Basics to Advanced Configuration and Optimization

Nginx Basics

Nginx is a lightweight, high‑performance web server and reverse‑proxy that excels at handling massive concurrent connections, making it a popular choice for sites like Baidu, JD.com, and Tencent.

Advantages of Nginx

Low memory footprint

Excellent concurrency handling

Built‑in reverse‑proxy and load‑balancing

Supports HTTP, HTTPS, SMTP, and IMAP/POP3

Installation

You can install Nginx via package managers (yum) or compile from source to add custom modules.

# yum install nginx
# rpm -ql nginx | grep log

Configuration File Structure

The main configuration /etc/nginx/nginx.conf is divided into global, events, and http sections. Inside http you define server blocks, each containing location blocks.

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log notice;
pid /var/run/nginx.pid;

events {
    worker_connections 1024;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;
    log_format main '$remote_addr - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" "$http_x_forwarded_for"';
    access_log /var/log/nginx/access.log main;
    sendfile on;
    keepalive_timeout 65;
    include /etc/nginx/conf.d/*.conf;
}

Virtual Hosts

Each server block defines a virtual host with directives such as listen, server_name, root, and index. Multiple virtual hosts can coexist by placing separate .conf files in /etc/nginx/conf.d/.

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

Logging

Nginx records access and error information using access_log and error_log. The log_format directive defines the log fields (IP, user, time, request, status, bytes, referrer, user‑agent, forward‑for). Log rotation is handled by /etc/logrotate.d/nginx.

# tail -f /var/log/nginx/access.log
# tail -f /var/log/nginx/error.log

Key Modules Overview

ngx_http_stub_status_module – provides connection statistics via stub_status.

ngx_http_random_index_module – serves a random index file for “micro‑updates”.

ngx_http_sub_module – on‑the‑fly content replacement with sub_filter.

ngx_http_gzip_module – compresses responses to save bandwidth.

ngx_http_limit_req_module and ngx_http_limit_conn_module – rate‑limit and connection‑limit per IP.

ngx_http_referer_module – basic hotlink protection.

ngx_http_auth_basic_module – simple username/password protection.

ngx_http_autoindex_module – directory listing.

Common Management Commands

# nginx -t            # test configuration syntax
# systemctl restart nginx   # reload changes
# nginx -V            # show compile options
# kill -USR2 <pid>    # graceful upgrade (for compiled installs)

By mastering these concepts you can deploy Nginx, fine‑tune performance, secure your sites, and extend functionality with additional modules.