Mastering Nginx: From Basics to High‑Availability Clusters

Nginx Overview

Nginx (engine x) is a high‑performance HTTP and reverse‑proxy server known for low memory usage and strong concurrency, used by major Chinese sites such as Baidu, JD, Sina, NetEase, Tencent, and Taobao.

1.1 Web Server

Nginx can serve static pages and, via CGI, dynamic languages like Perl and PHP, but not Java (requires Tomcat). It can handle up to 50,000 concurrent connections.

1.2 Reverse Proxy

Forward proxy: client configures proxy.

Reverse proxy: server handles proxy transparently.

1.3 Load Balancing

Nginx’s asynchronous architecture holds many concurrent requests and forwards them to backend servers, enabling safer host hiding, IP saving, and easy scaling.

1.4 Static‑Dynamic Separation

Separating static and dynamic content onto different servers reduces load and speeds up parsing.

Nginx serves static resources; Tomcat serves dynamic resources.

Installation and Startup

Required source packages: pcre‑8.37.tar.gz, openssl‑1.0.1t.tar.gz, zlib‑1.2.8.tar.gz, nginx‑1.11.1.tar.gz.

Installation steps include compiling pcre, openssl, zlib, then nginx with ./configure, make, make install.

Open firewall ports (e.g., firewall-cmd --add-service=http) and reload.

Nginx Startup Commands

Start: ./nginx in /usr/local/nginx/sbin

Stop: ./nginx -s stop Reload:

./nginx -s reload

Set Nginx as a Service

Edit /etc/rc.d/rc and add /usr/local/nginx/sbin/nginx.

Core Configuration File (nginx.conf)

The default configuration resides in the conf directory. It consists of three blocks: global, events, and http.

worker_processes  1;</code><code>events {</code><code>    worker_connections  1024;</code><code>}</code><code>http {</code><code>    include       mime.types;</code><code>    default_type  application/octet-stream;</code><code>    keepalive_timeout  65;</code><code>    server {</code><code>        listen       80;</code><code>        server_name  localhost;</code><code>        location / {</code><code>            root   html;</code><code>            index  index.html index.htm;</code><code>        }</code><code>    }</code><code>}

Explanation of each block follows.

Global Block

Sets directives affecting the whole server, such as user, worker_processes, PID path, and log locations.

Events Block

Controls connection handling; example sets worker_connections 1024.

HTTP Block

Contains most functional directives, including include, MIME types, logging, timeouts, and server definitions.

Server and Location Blocks

Define virtual hosts and request routing. Multiple location directives can match URLs with regex modifiers (=, ~, ~*, ^~).

Practical Configurations

Reverse Proxy Example

server {</code><code>    listen       80;</code><code>    server_name  localhost;</code><code>    location / {</code><code>        proxy_pass http://localhost:8001;</code><code>    }</code><code>    location ~ /demo1 {</code><code>        proxy_pass http://localhost:8001;</code><code>    }</code><code>    location ~ /demo2 {</code><code>        proxy_pass http://localhost:8002;</code><code>    }</code><code>}

Load Balancing Example

http{</code><code>  upstream myserver{</code><code>    ip_hash;</code><code>    server localhost:8080 weight=1;</code><code>    server localhost:8081 weight=1;</code><code>  }</code><code>  server{</code><code>    listen 80;</code><code>    server_name localhost;</code><code>    location / {</code><code>        proxy_pass http://myserver;</code><code>        proxy_connect_timeout 10;</code><code>    }</code><code>  }</code><code>}

Load‑balancing methods include round‑robin (default), weight, ip_hash, and third‑party fair.

Worker Process Tuning

Set worker_processes equal to CPU cores and configure worker_cpu_affinity for binding.

# Set worker number</code><code>worker_processes 4</code><code># Bind workers to CPUs</code><code>worker_cpu_affinity 0001 0010 0100 1000

worker_connections

defines the maximum connections per worker; total possible connections equal worker_processes * worker_connections.

High‑Availability Cluster

Combine Keepalived with Nginx for active‑passive (master‑slave) or active‑active (dual‑master) clusters.