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 {<br/>    worker_connections  1024;<br/>}

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

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

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

Static‑Dynamic Separation Example

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

High‑Availability Cluster Example

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

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

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.