Deploy Load Balanced Windows VMs with IIS on Azure using Terraform

🧭 Introduction

In this guide, we will deploy a pair of Windows Server 2022 virtual machines behind an Azure Load Balancer, automatically install IIS on them using a startup script, and configure NAT rules to allow RDP access. This is a great hands-on example to learn Infrastructure as Code (IaC) and understand how Azure Load Balancers distribute traffic.

本指南将通过 Terraform 创建两个 VM + 负载均衡器 + NAT 规则 + 自动 IIS 安装，适合练习云架构基础。

---

🗂 Project Structure

bash
terraform-lb-iis-vm/
├── main.tf                # All core infrastructure resources
├── variables.tf           # Input variables (e.g., username/password)
├── terraform.tfvars       # Actual values for variables
├── outputs.tf             # Output info (e.g., Public IP)
├── startup-script.ps1     # Script to install IIS on each VM

🔧 What This Code Does
Creates a Resource Group and Virtual Network

Defines a Public Load Balancer with Backend Pool

Sets up NAT rules for RDP (TCP 50001 & 50002)

Deploys two Windows Server VMs and installs IIS

Associates the VMs with the Load Balancer backend pool

This architecture allows HTTP access via Load Balancer's Public IP, and RDP access via port NAT.

🪜 How to Deploy
Make sure you have:

Azure CLI installed and logged in (az login)

Terraform installed locally

Steps:
terraform init
terraform plan
terraform apply

When prompted, type yes.


🌐 Access Instructions
VM1 RDP: RDP to PublicIP:50001

VM2 RDP: RDP to PublicIP:50002

HTTP Test: http://PublicIP (should show IIS welcome page)



✅ Conclusion
Using only Terraform, we have:

Created two VMs

Configured a Load Balancer and NAT

Installed IIS automatically via startup script

This project demonstrates how to combine multiple Azure services in an automated and repeatable way. It’s a foundational building block for scalable web applications.

🔜 Coming Next...
Use Azure Run Command to manage VMs remotely

Add autoscaling rules for backend VMs

Integrate with Azure Monitor for health probes

If you find this helpful, feel free to ⭐️ the repo and share your feedback!