Master Nginx: From Basic Commands to Advanced Reverse Proxy & Load Balancing

Overview

What is Nginx? Nginx (engine x) is a lightweight web server, reverse proxy server, and mail (IMAP/POP3) proxy server.

What is a Reverse Proxy?

A reverse proxy accepts Internet connection requests, forwards them to internal servers, and returns the response to the client, acting as the external entry point.

Usage

Common Nginx commands:

<code>nginx -s stop       # fast stop, may not save state
nginx -s quit       # graceful stop, saves state
nginx -s reload     # reload after configuration change
nginx -s reopen     # reopen log file
nginx -c filename   # specify a configuration file
nginx -t            # test configuration syntax only
nginx -v            # show Nginx version
nginx -V            # show version, compiler and configure parameters</code>

To avoid typing commands each time, create a

startup.bat

in the Nginx installation directory:

<code>@echo off
rem If Nginx is already running and a pid file exists, kill the process
nginx.exe -s stop
rem Test configuration syntax
nginx.exe -t -c conf/nginx.conf
rem Show version information
nginx.exe -v
rem Start Nginx with a specific configuration
nginx.exe -c conf/nginx.conf</code>

On Linux, a similar shell script can be used.

Nginx Configuration Practice

Goal: implement a simple HTTP reverse proxy without complex settings.

<code># user somebody;
worker_processes  1;
error_log  D:/Tools/nginx-1.10.1/logs/error.log;
error_log  D:/Tools/nginx-1.10.1/logs/notice.log  notice;
error_log  D:/Tools/nginx-1.10.1/logs/info.log  info;
pid        D:/Tools/nginx-1.10.1/logs/nginx.pid;

events {
    worker_connections 1024;
}

http {
    include       D:/Tools/nginx-1.10.1/conf/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    D:/Tools/nginx-1.10.1/logs/access.log main;
    rewrite_log     on;
    sendfile        on;
    keepalive_timeout  120;
    tcp_nodelay        on;
    upstream zp_server1 {
        server 127.0.0.1:8089;
    }
    server {
        listen       80;
        server_name  www.helloworld.com;
        index index.html;
        root D:\01_Workspace\Project\github\zp\SpringNotes\spring-security\spring-shiro\src\main\webapp;
        charset utf-8;
        proxy_connect_timeout 180;
        proxy_send_timeout 180;
        proxy_read_timeout 180;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarder-For $remote_addr;
        location / {
            proxy_pass http://zp_server1;
        }
        location ~ ^/(images|javascript|js|css|flash|media|static)/ {
            root D:\01_Workspace\Project\github\zp\SpringNotes\spring-security\spring-shiro\src\main\webapp\views;
            expires 30d;
        }
        location /NginxStatus {
            stub_status           on;
            access_log            on;
            auth_basic            "NginxStatus";
            auth_basic_user_file  conf/htpasswd;
        }
        location ~ \.ht {
            deny all;
        }
    }
}
</code>

Test steps:

Start the webapp, ensuring the port matches the upstream server.

Add a DNS entry

127.0.0.1 www.helloworld.com

to the hosts file.

Run

startup.bat

to launch Nginx.

Visit

http://www.helloworld.com

in a browser.

Load Balancing Configuration

Example with three backend servers and weighted distribution:

<code>http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;
    access_log    /var/log/nginx/access.log;
    upstream load_balance_server {
        server 192.168.1.11:80 weight=5;
        server 192.168.1.12:80 weight=1;
        server 192.168.1.13:80 weight=6;
    }
    server {
        listen       80;
        server_name  www.helloworld.com;
        location / {
            root        /root;
            index       index.html index.htm;
            proxy_pass  http://load_balance_server;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $remote_addr;
            proxy_connect_timeout 90;
            proxy_send_timeout 90;
            proxy_read_timeout 90;
            proxy_buffer_size 4k;
            proxy_buffers 4 32k;
            proxy_busy_buffers_size 64k;
            client_max_body_size 10m;
            client_body_buffer_size 128k;
        }
    }
}
</code>

Multiple Webapp Configuration

Separate upstream blocks for product, admin, and finance services, routing based on URL path:

<code>http {
    upstream product_server { server www.helloworld.com:8081; }
    upstream admin_server   { server www.helloworld.com:8082; }
    upstream finance_server { server www.helloworld.com:8083; }
    server {
        # default to product
        location / { proxy_pass http://product_server; }
        location /product/ { proxy_pass http://product_server; }
        location /admin/   { proxy_pass http://admin_server; }
        location /finance/ { proxy_pass http://finance_server; }
    }
}
</code>

HTTPS Reverse Proxy Configuration

Listen on port 443 with SSL certificates and standard proxy settings:

<code>server {
    listen       443 ssl;
    server_name  www.helloworld.com;
    ssl_certificate      cert.pem;
    ssl_certificate_key  cert.key;
    ssl_session_cache    shared:SSL:1m;
    ssl_session_timeout  5m;
    ssl_ciphers  HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers  on;
    location / {
        root   /root;
        index  index.html index.htm;
    }
}
</code>

Static Site Configuration

Serve a static site from

/app/dist

with gzip compression:

<code>worker_processes  1;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;
    sendfile        on;
    keepalive_timeout  65;
    gzip on;
    gzip_types text/plain application/x-javascript text/css application/xml text/javascript application/javascript image/jpeg image/gif image/png;
    gzip_vary on;
    server {
        listen       80;
        server_name  static.zp.cn;
        location / {
            root /app/dist;
            index index.html;
        }
    }
}
</code>

File Server Setup

Enable directory listing and serve files from

/share/fs

on port 9050:

<code>autoindex on;
autoindex_exact_size on;
autoindex_localtime on;

server {
    charset      utf-8,gbk;
    listen       9050 default_server;
    listen       [::]:9050 default_server;
    server_name  _;
    root         /share/fs;
}
</code>

Cross‑Origin Solution

Two approaches: CORS (setting response headers) and JSONP. Nginx can implement CORS via an include file.

<code># enable-cors.conf
set $ACAO '*';
if ($http_origin ~* (www.helloworld.com)$) { set $ACAO $http_origin; }
if ($cors = "trueget") {
    add_header 'Access-Control-Allow-Origin' "$http_origin";
    add_header 'Access-Control-Allow-Credentials' 'true';
    add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
    add_header 'Access-Control-Allow-Headers' 'DNT,X-Mx-ReqToken,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';
}
if ($request_method = 'OPTIONS') { set $cors "${cors}options"; }
if ($request_method = 'GET')    { set $cors "${cors}get"; }
if ($request_method = 'POST')   { set $cors "${cors}post"; }
</code>

<code># main server block
upstream front_server { server www.helloworld.com:9000; }
upstream api_server   { server www.helloworld.com:8080; }

server {
    listen       80;
    server_name  www.helloworld.com;
    location ~ ^/api/ {
        include enable-cors.conf;
        proxy_pass http://api_server;
        rewrite "^/api/(.*)$" /$1 break;
    }
    location / {
        proxy_pass http://front_server;
    }
}
</code>

All configurations above demonstrate how to use Nginx for reverse proxy, load balancing, HTTPS, static content, file serving, and CORS handling.