Overview

Load balancing across multiple application instances is a commonly used technique for optimizing resource utilization, maximizing throughput, reducing latency, and ensuring fault-tolerant configurations.

Requirements

We need atleast 3 Ubuntu Box, In my scenario setup is like this

192.168.138.129 = Nginx Load Balancer

192.168.138.132 = Nginx Web01

192.168.138.133 = Nginx Web02

Steps - Log on to Web01 server using root privileges

• Install Nginx

#!html

root@web01:~# apt install nginx

• Once installation is completed start Nginx using bellow command

#!html

root@web01:~# systemctl start nginx

Change Nginx default page text with an identical name

• Open Nginx default page from below command

#!html

root@web01:~# vi /var/www/html/index.nginx-debian.html

• Change

  Welcome to nginx!

  replace with this

  Web01 nginx!

• Now Web01 Default web page will look like below Image

Log on to Web02 server using root privileges

• Install Nginx

#!html

root@web02:~# apt install nginx

• Once installation is completed start Nginx using bellow command

#!html

root@web02:~# systemctl start nginx

Change Nginx default page text with an identical name

• Open Nginx default page from below command

#!html

root@web02:~# vi /var/www/html/index.nginx-debian.html

• Change

  Welcome to nginx!

  replace with this

  Web02 nginx!

• Now Web02 Default web page will look like below Image

Now Logon to Nginx LB server using root privilege

• Install Nginx

#!html

root@LB:~# apt install nginx

• Once installation is completed start Nginx using bellow command

#!html

root@LB:~# systemctl start nginx

• Now edit Nginx configuration file so that this server will act as LB and send the client request to Web01 and Web02 server.

#!html

root@LB:~# vi /etc/nginx/sites-available/default

Comment all open line and go to end of this file

• Add below mentioned syntax end of this file and your's config file looks like below

#!html

        upstream web_rack {
            server 192.168.138.132;
            server 192.168.138.133;
        }
        server {
           listen 80;
        server_name 192.168.138.129;
           location / {
                proxy_pass http://web_rack;
    }
}

* Save file and exit.

• Restart Nginx using below command.

#!html

root@LB:~# systemctl restart nginx

*Now Open Browser and hit LB IP address

• See below image result for first hit

• See below image result for Second hit

• ByDefault Nginx load balancer work as round robin method.