Comprehensive Guide to Nginx Configuration, Reverse Proxy, Load Balancing, and High‑Availability Clusters

Nginx is a high‑performance HTTP and reverse‑proxy server known for low memory usage and strong concurrency, capable of handling up to 50,000 simultaneous connections.

Key Functions

Forward proxy – requires client‑side configuration.

Reverse proxy – transparent to clients, hides backend server IPs.

Load balancing – distributes requests across multiple servers.

Static‑dynamic separation – serves static assets from dedicated servers to improve performance.

Configuration File Structure

The main configuration file ( /usr/local/nginx/conf/nginx.conf ) consists of a global block, an events block, and an http block.

worker_processes  1;

The global block sets user, worker processes, PID path, and log settings.

events {
worker_connections  1024;
}

The http block contains global HTTP settings, server blocks, and optional location blocks.

Reverse Proxy Example

Goal: Access Tomcat’s homepage via Nginx.

worker_processes  1;
events {
worker_connections  1024;
}
http {
include       mime.types;
default_type  application/octet-stream;
sendfile        on;
keepalive_timeout  65;
server {
listen       80;
server_name  192.168.71.167;
location / {
root   html;
proxy_pass http://127.0.0.1:8080;
index  index.html index.htm;
}
error_page   500 502 503 504  /50x.html;
location = /50x.html {
root   html;
}
}
}

Reload configuration with:

/usr/local/nginx/sbin/nginx -s reload

Load Balancing Example

Goal: Distribute requests between two Tomcat instances (ports 8080 and 8081).

worker_processes  1;
events {
worker_connections  1024;
}
http {
include       mime.types;
default_type  application/octet-stream;
sendfile        on;
keepalive_timeout  65;
upstream myserver{
server 192.168.71.167:8080 weight=1;
server 192.168.71.167:8081 weight=1;
}
server {
listen       80;
server_name  192.168.71.167;
location / {
root   html;
proxy_pass http://myserver;
proxy_connect_timeout 10;
index  index.html index.htm;
}
error_page   500 502 503 504  /50x.html;
location = /50x.html {
root   html;
}
}
}

Common load‑balancing strategies include round‑robin (default), weight‑based, ip_hash , and third‑party fair modules.

Static‑Dynamic Separation Example

worker_processes  1;
events {
worker_connections  1024;
}
http {
include       mime.types;
default_type  application/octet-stream;
sendfile        on;
keepalive_timeout  65;
server {
listen       80;
server_name  192.168.71.167;
location /www/ {
root   /data/;
index  index.html index.htm;
}
location /image/ {
root   /data/;
autoindex on;
}
error_page   500 502 503 504  /50x.html;
location = /50x.html {
root   html;
}
}
}

High‑Availability Cluster Example

Two machines run Keepalived, Nginx, and Tomcat. Keepalived provides a virtual IP (VIP) with master‑backup failover.

global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id 192.168.71.167
}
vrrp_script nginx_check {
script "/usr/local/src/nginx_check.sh"
interval 1
weight -30
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.71.100
}
track_script { nginx_check }
}

The backup node has a similar configuration with state BACKUP and a lower priority.

These examples illustrate how to configure Nginx for common enterprise scenarios, from basic reverse proxy to load balancing, static‑dynamic separation, and high‑availability clustering.