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Alao Abdul-zahir
Alao Abdul-zahir

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🚀 Building a Multi-Environment, Auto-Scaling Web Platform with Terraform

#terraform #infrastructureascode #devops

Managing cloud infrastructure by hand can be messy, especially when juggling multiple environments like dev, staging, and prod. That’s where Terraform shines – it lets you define your infrastructure as code, making your deployments consistent, repeatable, and version-controlled.

In this post, I’ll walk you through building a production-ready web application infrastructure on AWS using Terraform. We’ll cover:

  • 🔹 Multi-environment setup (dev & prod)
  • 🔹 VPC with public/private subnets
  • 🔹 Auto Scaling Group with EC2 instances
  • 🔹 RDS database layer
  • 🔹 Secure backend state management
  • 🔹 Secrets scanning with git-secrets

🏗️ Project Overview

We’re building a simple yet scalable platform:

Internet
   ↓
Application Load Balancer (ALB)
   ↓
Auto Scaling Group (EC2 Instances)
   ↓
RDS Database (MySQL)
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This setup ensures high availability, cost optimization, and easy environment promotion (from dev to prod).

📂 Project Structure

We organize Terraform code using modules for reusability:

terraform-web-platform/
├── environments/
│   ├── dev/
│   │   ├── main.tf
│   │   └── terraform.tfvars
│   └── prod/
│       ├── main.tf
│       └── terraform.tfvars
├── modules/
│   ├── networking/
│   ├── compute/
│   ├── database/
│   └── monitoring/
└── README.md
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🔑 Key Features

✅ Multi-Environment Setup – Each environment has its own state and variables.

✅ Terraform Modules – Networking, compute, database, and monitoring are modularized.

✅ Secure State Management – Remote state stored in S3 with DynamoDB locking.

✅ Auto Scaling – EC2 instances scale based on CPU utilization.

✅ Monitoring – CloudWatch metrics and alarms for visibility.

🛠️ Setup Instructions

1. Clone the Repo 

git clone https://github.com/pojava/terraform-web-platform.git
cd terraform-web-platform
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2. Configure AWS Credentials 

aws configure
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Provide your AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, region, and output format.

3. Initialize and Apply Terraform 

cd environments/dev
terraform init
terraform plan
terraform apply
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To deploy to production:

cd ../prod
terraform init
terraform plan
terraform apply
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4. Check the Load Balancer

Once deployed, Terraform outputs the ALB DNS. Visit it in your browser to verify your app is live.

🔒 Security Practices

  • No Hardcoded Secrets: All sensitive values are managed through environment variables or AWS Secrets Manager.
  • git-secrets Installed: Prevents accidentally committing API keys.
  • .gitignore Applied: Ignores Terraform state and provider files.

🧹 Cleaning Up

When you’re done testing, destroy resources to avoid costs:

terraform destroy
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📝 Lessons Learned

  • Using Terraform modules keeps your code DRY and maintainable.
  • Remote state locking prevents accidental overwrites during team deployments.
  • AWS Auto Scaling ensures your application stays resilient without overspending.

🔗 Useful Resources

🚀 Final Thoughts

This project shows how to go from zero to a production-ready, auto-scaling infrastructure using Terraform. By structuring code with modules and managing state securely, scaling your app becomes a breeze.

If you found this useful, ⭐️ the repo and drop a comment on Dev.to!

🔗 GitHub Repo

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