Master Nginx: Basics, Reverse Proxy, Load Balancing & High Availability

What is Nginx?

Nginx is a high‑performance HTTP server and reverse proxy that uses little memory and can handle tens of thousands of concurrent connections.

Key Features

Designed for performance, Nginx can support up to 50 000 concurrent connections.

Architecture Overview

Nginx knowledge‑map structure:

Proxy Types

Forward proxy: LAN clients must access the Internet through a proxy server.

Reverse proxy: Clients send requests to the reverse‑proxy server, which forwards them to backend servers and returns the response, hiding the real server IP.

Load Balancing

Distribute client requests across multiple backend servers to improve scalability. Example: 15 requests are split evenly among three servers (5 each).

Static‑Dynamic Separation

Serve static files with Nginx and dynamic content with Tomcat to accelerate page rendering.

Installation on Linux

Typical commands to manage Nginx:

./nginx -v

./nginx

./nginx -s stop

./nginx -s quit

./nginx -s reload

Configuration File Structure

The nginx.conf consists of three blocks:

global – settings that affect the whole server.

events – network connection handling.

http – reverse proxy, load balancing, etc.

Example location directive syntax:

location [ = | ~ | ~* | ^~ ] url {

# configuration

}

Reverse Proxy Practical Example

Configure Nginx to forward www.123.com (or 192.168.25.132:9001/edu/) to Tomcat instances on ports 8080 and 8081 using regular expressions.

Load Balancing Practical Example

Modify nginx.conf to define an upstream group and reload Nginx.

Supported algorithms: round‑robin (default), weight, fair, ip_hash.

High‑Availability with Keepalived

Install Keepalived, configure a virtual IP, and set up health‑check scripts so that if the primary Nginx fails, the backup takes over.

# yum install keepalived -y

# systemctl start keepalived.service

Worker‑Master Model

Nginx runs a master process that manages multiple worker processes; the number of workers should match the CPU core count for optimal performance.