AWS Application Load Balancer (Mini Project)

Overview

This project walks through deploying an Application Load Balancer (ALB) in AWS to evenly distribute traffic across three EC2 instances.
Each instance (named Home, Laptop, and Mobile) hosts a custom Apache web page. The ALB is then configured to route incoming requests and verify distribution by refreshing the DNS link.

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Architecture Summary

1. EC2 Instances

   • Launch 3 Amazon Linux t2.micro instances (Free Tier).
   • Use User Data scripts to install Apache (httpd) and serve unique pages.

2. Target Groups

   • Create three target groups (one per instance).
   • Register each instance to its respective target group.

3. Application Load Balancer

   • Create an ALB and attach the target groups.
   • Configure HTTP:80 listener to forward traffic.

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Implementation Steps

Step 1: Launch EC2 Instances

For each instance, use a User Data script to install Apache and serve a custom page.

Home Instance

#!/bin/bash
yum update -y
yum install -y httpd
systemctl start httpd
systemctl enable httpd
echo "<h1> Welcome to the Home Page - $(hostname -f)</h1>" > /var/www/html/index.html

Laptop Instance

#!/bin/bash
yum update -y
yum install -y httpd
systemctl start httpd
systemctl enable httpd
mkdir /var/www/html/laptop
echo "<h1> Laptop Page - $(hostname -f)</h1>" > /var/www/html/laptop/index.html

Mobile Instance

#!/bin/bash
yum update -y
yum install -y httpd
systemctl start httpd
systemctl enable httpd
mkdir /var/www/html/mobile
echo "<h1> Mobile Page - $(hostname -f)</h1>" > /var/www/html/mobile/index.html

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Step 2: Configure Target Groups

• In the AWS Console → Target Groups, create 3 target groups.
• Register each instance under its group (Home → TG-Home, Laptop → TG-Laptop, Mobile → TG-Mobile).
  

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Step 3: Create Application Load Balancer

• Go to EC2 → Load Balancers → Create ALB.
• Add the three target groups.
• Configure Listener on Port 80 (HTTP) to forward requests to the groups.
  

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Step 4: Test the Load Balancer

• Copy the ALB DNS name from the console.
• Paste it into a browser and refresh multiple times.
• You should alternately see:
  • Home instance response
  • Laptop instance response
  • Mobile instance response
    

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Expected Output

• Home Page: This is the Home Instance

• Laptop Page: This is the Laptop Instance

• Mobile Page: This is the Mobile Instance

Conclusion

We successfully set up an Application Load Balancer in AWS that distributes requests across three EC2 servers. Each instance serves a custom page, and the ALB ensures traffic is shared evenly, verifying the load balancing feature.

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