User
↓
Application Load Balancer (Public Subnet)
↓
Target Group
↓
Auto Scaling Group
↓
Private EC2 Instances (Apache Web Server)
↓
NAT Gateway → Internet (Outbound Only)

🚀 AWS Application Load Balancer with Auto Scaling (Real-World Project)

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📌 Project Overview

This project demonstrates a real-world, production-style AWS architecture where a web application runs securely on private EC2 instances behind an Application Load Balancer (ALB) with Auto Scaling Group (ASG).

The infrastructure is designed following AWS best practices for:

• 🔐 Security
• 📈 Scalability
• 🌍 High Availability

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🏗️ Architecture Diagram (Logical Flow)

User
↓
Application Load Balancer (Public Subnet)
↓
Target Group
↓
Auto Scaling Group
↓
Private EC2 Instances (Apache Web Server)
↓
NAT Gateway → Internet (Outbound Only)

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🧰 AWS Services Used

• Amazon VPC
• Amazon EC2 (Ubuntu)
• Application Load Balancer (ALB)
• Auto Scaling Group (ASG)
• Target Groups
• NAT Gateway
• Internet Gateway
• Security Groups

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⚙️ Key Features

✅ EC2 instances run in private subnets (no public IP) ✅ Internet access only through ALB ✅ Outbound internet via NAT Gateway ✅ Auto Scaling based on demand ✅ Highly available across multiple AZs

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🪜 Step-by-Step Implementation

1️⃣ VPC Creation

• Custom VPC with CIDR: 10.0.0.0/16

2️⃣ Subnets

• Public Subnets → ALB & NAT Gateway
• Private Subnets → EC2 instances

3️⃣ Internet Gateway

• Attached to VPC for inbound internet traffic

4️⃣ NAT Gateway

• Created in public subnet
• Enables outbound internet for private EC2

5️⃣ Security Groups

ALB Security Group

• Allow HTTP (80) from 0.0.0.0/0

EC2 Security Group

• Allow HTTP (80) only from ALB SG

6️⃣ Launch Template

• Ubuntu AMI
• Apache installed using User Data script

7️⃣ Target Group

• Target type: Instance
• Protocol: HTTP (80)
• Health check path: /

8️⃣ Application Load Balancer

• Internet-facing
• Listener on port 80
• Attached to target group

9️⃣ Auto Scaling Group

• Min: 1
• Desired: 2
• Max: 3
• Integrated with ALB

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📜 User Data Script (Ubuntu EC2)

#!/bin/bash
apt update -y
apt install -y apache2
systemctl start apache2
systemctl enable apache2

echo "<h1>AWS ALB + Auto Scaling Web Server</h1><h2>Hostname: $(hostname)</h2>" > /var/www/html/index.html

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🧪 Verification Steps

1. Copy ALB DNS name
2. Open browser:

http://<ALB-DNS-NAME>

1. Refresh page multiple times
2. Observe different hostnames (load balancing working)

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✅ Final Outcome

✔ Secure architecture with no public EC2 IPs ✔ Load balancing across multiple instances ✔ Auto scaling handles traffic automatically ✔ Production-grade AWS setup

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🧠 Key Learnings

• Designing secure AWS VPC architecture
• Load balancing & auto scaling concepts
• Real-world cloud networking
• Hands-on AWS infrastructure deployment

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📌 Use Cases

• Enterprise web applications
• Microservices backend
• Scalable production workloads

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👨‍💻 Author

Irfan Pasha Cloud Engineer | AWS Enthusiast

🔗 GitHub:https://github.com/yourusername 🔗 DEV: https://dev.to/yourusername

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