Section 1: End-to-End Auto Scaling with ALB

Architecture

• ALB distributes traffic to EC2 instances in multiple AZs
• ASG launches and terminates instances automatically
• CloudWatch metrics control scaling events

Steps

Step 1: Create Launch Template

• AMI: Amazon Linux 2
• t2.micro
• SG: allow HTTP
• User Data (simple app):

#!/bin/bash
sudo yum update -y
sudo yum install -y httpd
echo "Hello from kaptaindevops ASG instance" > /var/www/html/index.html
sudo systemctl start httpd
sudo systemctl enable httpd

Step 2: Create Target Group (HTTP 80)

Step 3: Create Application Load Balancer

• Internet facing
• Add listener HTTP :80
• Attach target group

Step 4: Create ASG

• Choose Launch Template