🚀 Terraform AWS NGINX ASG + ALB Web Server

This project provisions a scalable NGINX web server environment on AWS using Terraform. It demonstrates real-world Infrastructure as Code (IaC) practices including custom networking, security configuration, auto-scaling, load balancing and automated server provisioning without manual intervention.

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🏗️ Terraform driven Architecture Overview

The infrastructure deployed via Terraform includes:

• Custom VPC – 10.0.0.0/16
• Public Subnet in multiple Availability Zones (for ALB)
• Private Subnet in multiple Availability Zones (for ASG instances)
• Internet Gateway for outbound traffic to the internet
• Route Table for proper network routing
• Security Group allowing:
  • ALB Security Group – allows HTTP (80) and HTTPS (443) from the internet
  • ASG Instances Security Group – allows HTTP from ALB and SSH from admin IP
• Launch Template to provision EC2 instances with NGINX
• Auto Scaling Group (ASG) to manage EC2 instances
• Application Load Balancer (ALB) to distribute traffic across ASG instances
• Target Group for ALB to route traffic to ASG instances

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High-level Terraform Architecture Diagram:

Everything above is fully defined and managed via Terraform, demonstrating IaC principles.

🌍 Result

Once deployed, Terraform provisions:

• NGINX web server instances running in private subnets
• Fully functional Application Load Balancer with public access
• Auto Scaling to maintain desired instance count The page served displays:

Hello from Terraform via NGINX ASG!

Terraform outputs the ALB URL for easy access

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🛠️ Key Terraform Concepts Demonstrated

Concept	Description
Terraform	Infrastructure as Code
Providers	ProvidersConfigures AWS as the target cloud platform
Resources	Defines VPC, subnets, EC2 instances, security groups, ALB, ASG
Variables	Parameterizes inputs like SSH IP or instance types
Outputs	Exposes ALB URL and other useful info
User Data	Automates server setup (NGINX) on instance boot
Modules	Infrastructure can be modularized for reuse
Dependencies	Terraform ensures resources are created in the correct order

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📁 Project Structure

terraform-aws-nginx-asg-alb/
│
├── main.tf          # Core infrastructure resources (VPC, ALB, ASG, Launch Template)
├── variables.tf     # Input variables
├── provider.tf      # AWS provider configuration
├── outputs.tf       # Output values (ALB URL, Subnet IDs, Security Group IDs)
├── README.md        # Project documentation
└── .gitignore       # Files excluded from Git

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▶️ How to Deploy

1️⃣ Clone Repository

git clone https://github.com/thomasasamba-bot/terraform-aws-nginx-asg-alb.git
cd terraform-aws-nginx-asg-alb

2️⃣ Initialize Terraform

terraform init

3️⃣ Provide Your Public IP for SSH Access

export TF_VAR_my_ip="YOUR_PUBLIC_IP/32"

Example:

export TF_VAR_my_ip="41.90.162.115/32"

4️⃣ Deploy Infrastructure

terraform apply

Type yes when prompted.

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🌐 Access the NGINX Server

After deployment, Terraform will output:

load_balancer_url = http://<ALB-DNS-NAME>

Paste the URL into your browser to see the hosted NGINX page.

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🔐 Security Notes

• SSH access is restricted to a single admin IP address
• ALB handles public traffic; EC2 instances remain in private subnets
• No credentials or private keys are stored in the repository
• Infrastructure changes are fully managed by Terraform – no manual steps

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🧹 Destroy Infrastructure - Cleanup (Avoid AWS Charges)

terraform destroy --auto-approve

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📚 Key Learning Outcomes

This project demonstrates ability to:

• Building AWS infrastructure fully via Terraform
• Automating server setup using user_data
• Implementing Auto Scaling and Load Balancing
• Managing networking and security with Terraform resources
• Following IaC best practices for reproducible deployments

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👤 Author

Thomas
Cloud & DevOps Engineer ☁️🚀