Comprehensive Guide to Nginx: Introduction, Installation, Configuration, and Advanced Features

1. Introduction to Nginx Nginx is a free, open‑source, high‑performance HTTP and reverse‑proxy server that also supports IMAP/POP3 mail proxy, known for low memory usage and strong concurrency.

It consists of a core and various modules: core modules (HTTP, EVENT, MAIL), basic modules (HTTP Access, FastCGI, Proxy, Rewrite), and third‑party modules (Upstream, Notice, Access Key, custom). Extensions include the open‑source version, NGINX Plus, Tengine, and OpenResty.

2. Nginx as a Web Server Nginx serves static files and can proxy dynamic content (e.g., PHP, Perl) but does not run Java directly; Java apps typically run behind Tomcat.

3. Forward and Reverse Proxy Forward proxy mediates client requests to the Internet, while reverse proxy receives external requests and forwards them to internal servers, providing benefits such as resource hiding, SSL offloading, caching, and load balancing.

4. Load Balancing and URL Rewrite Nginx supports load‑balancing via the upstream block with strategies like round‑robin, weighted, ip_hash, fair, and url_hash. URL rewriting is performed with the rewrite directive using regular expressions and flags (last, break, redirect, permanent).

5. Installation Steps

wget http://nginx.org/download/nginx-1.16.1.tar.gz

yum install gcc c++
 yum install -y pcre pcre-devel
 yum install -y zlib zlib-devel
 yum install -y openssl openssl-devel

tar -zxvf nginx-1.15.tar.gz
 cd nginx-1.16.1
 ./configure
 make && sudo make install

cd /usr/local/nginx/sbin
 ./nginx
 ./nginx -s stop
 ./nginx -s reload
 ./nginx -t

6. Configuration File Structure The nginx.conf is divided into global, events , and http blocks. Example snippets:

user nobody;
worker_processes 4;
error_log /data/nginx/logs/error.log notice;

events {
    use epoll;
    worker_connections 1024;
    keepalive_timeout 60;
}

http {
    include mime.types;
    default_type application/octet-stream;
    sendfile on;
    keepalive_timeout 65;
    server {
        listen 80;
        server_name localhost;
        location / {
            root html;
            index index.html index.htm;
        }
    }
}

7. Practical Demo Configurations Includes reverse‑proxy demos, load‑balancing setups, and static‑dynamic separation using location blocks with proxy_pass , expires , and caching directives.

8. High Availability Describes a dual‑node Keepalived solution using VRRP to provide failover for Nginx, with sample keepalived.conf and health‑check script.

9. Performance Optimization Recommendations: set worker_processes equal to CPU cores, maximize worker_connections , enable Gzip, cache static assets, and optionally disable access logs.

10. Module Development Overview of compiling Nginx with custom modules using ./configure --add-module=path and a table of common configure options.

11. Interview Questions A collection of typical Nginx interview topics such as core features, common commands, differences from Apache, load‑balancing methods, and optimization techniques.