AWS Three-Tier Architecture with Terraform

A highly available three-tier web application infrastructure deployed on AWS using Terraform.

Overview

This project demonstrates how to deploy a three-tier architecture on AWS using Infrastructure as Code (IaC) with Terraform.

The architecture includes:

• Web Tier: Application Load Balancer
• Application Tier: EC2 Auto Scaling Group
• Database Tier: Amazon RDS MySQL

The infrastructure is designed with AWS best practices including:

• Public and private subnets
• Security group isolation
• IAM roles
• Multi-AZ networking

Architecture

            Internet
               |
               |
          ALB (Public)
               |
         Target Group
               |
    ---------------------
    |                   |
 EC2 ASG            EC2 ASG

Private subnet Private subnet | | RDS Private subnet

AWS Services Used

Networking

• Amazon VPC
• Public/Private Subnets
• Internet Gateway
• NAT Gateway
• Route Tables

Compute

• Amazon EC2
• Launch Template
• Auto Scaling Group

Load Balancing

• Application Load Balancer
• Target Group

Database

• Amazon RDS MySQL

Security

• IAM Role
• Security Groups

Infrastructure as Code

• Terraform

Project Structure

aws-three-tier/

├── providers.tf

├── versions.tf

├── variables.tf

├── vpc.tf

├── subnet.tf

├── route-table.tf

├── nat.tf

├── security_group.tf

├── iam.tf

├── launch_template.tf

├── autoscaling.tf

├── alb.tf

├── target-group.tf

├── alb-attachment.tf

├── rds.tf

└── outputs.tf

Deployment

Initialize Terraform:

terraform init
terraform validate
terraform plan
terraform apply

Outputs

• After deployment:

terraform output

Cleanup

• To remove all AWS resources:

terraform destroy

Future Improvements

• Add HTTPS with ACM certificate
• Add Route53 DNS
• Store database credentials in AWS Secrets Manager
• Add Terraform remote backend with S3 and DynamoDB locking
• Add CI/CD pipeline using GitHub Actions

Architecture Diagram

Maintenance

• Upgraded Amazon RDS for MySQL from 8.0.46 to 8.4.9 using Terraform.
• Enabled major version upgrade support and applied the change immediately.
• Verified that Terraform state matches AWS resources after upgrade.