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Ahkar Swe
Ahkar Swe

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🏗️ Building a 3-Tier Architecture with Terraform (ALB + EC2 + DB) — Part 9

#architecture #aws #terraform #tutorial

So far in this series, we’ve:

  • Built Terraform fundamentals
  • Created reusable modules
  • Designed production-ready structure
  • Compared workspaces vs environments
  • Deployed a VPC with Terraform

Now it’s time to build something closer to real production 🔥

👉 A 3-tier architecture on AWS

🎯 What You’ll Learn

In this guide:

  • What 3-tier architecture is
  • How AWS components work together
  • How to design scalable infrastructure
  • Terraform-based architecture thinking

🏗️ What is 3-Tier Architecture?

A 3-tier architecture separates your system into:

1. Presentation Layer (ALB)
2. Application Layer (EC2)
3. Data Layer (Database)
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🌐 Architecture Overview 

Internet
   ↓
ALB (Load Balancer)
   ↓
EC2 Instances (App)
   ↓
RDS (Database)
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🔹 Layer 1: Load Balancer (ALB)

  • Handles incoming traffic
  • Distributes requests
  • Improves availability

👉 Entry point of your system

🔹 Layer 2: Application (EC2)

  • Runs your app (Node.js, PHP, etc.)
  • Can scale horizontally
  • Connected to ALB

🔹 Layer 3: Database (RDS)

  • Stores data
  • Private (not exposed to internet)
  • Secured via subnet + security group

🧠 DevOps Insight

👉 This architecture is used in:

  • Web applications
  • SaaS platforms
  • Enterprise systems

🔧 Terraform Design Approach

Instead of writing everything in one file:

👉 Break into components:

modules/
  vpc/
  alb/
  ec2/
  rds/
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🔹 Example: ALB Resource 

resource "aws_lb" "app_lb" {
  name               = "app-lb"
  load_balancer_type = "application"
  subnets            = var.public_subnets
}
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🔹 Example: EC2 Layer 

resource "aws_instance" "app" {
  ami           = var.ami
  instance_type = "t2.micro"
}
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🔹 Example: RDS 

resource "aws_db_instance" "db" {
  allocated_storage = 20
  engine            = "mysql"
  instance_class    = "db.t3.micro"
}
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🔐 Security Design (Important)

  • ALB → Public
  • EC2 → Private
  • RDS → Private

👉 Use Security Groups to control access

🚀 Deployment Flow

```bash id="3tier7"
terraform init
terraform plan
terraform apply




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## 🧠 What You Just Built

You now understand:

* Real-world AWS architecture
* Multi-layer infrastructure
* Terraform design patterns

👉 This is production-level thinking.

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## ⚠️ Important Note

3-tier architecture introduces:

* More cost
* More complexity

👉 Always destroy resources when not needed

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## 🎯 What You Just Learned

* 3-tier system design
* AWS service integration
* Terraform architecture mindset

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## 💡 Final Thought

This is where Terraform becomes powerful.

👉 You are no longer deploying resources.

👉 You are designing systems.

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## 🚀 What’s Next?

Next, we go automation:

👉 Terraform + CI/CD (GitHub Actions)

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## 👨‍💻 About the Author

Hi, I’m Ahkar — sharing DevOps, AWS, and Infrastructure knowledge 🚀

🌐 https://mindgnite.com

Follow for more Terraform content 🔥

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## 📚 Terraform Learning Series

* Part 8: VPC Lab
* Part 9: 3-Tier Architecture (this post)
* Part 10: CI/CD with Terraform

👉 Follow to continue 🚀
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