Terraform GCP VM Module

This repository provisions a VM instance on Google Cloud Platform using Terraform.

📁 Structure

terraform-gcp-vm/
├── main.tf
├── variables.tf
├── modules/
│   └── gcp_vm/
│       ├── main.tf
│       └── variables.tf

✅ Features

• Creates a GCP Compute Engine instance
• Accepts parameters: instance type, zone, image
• Installs nginx via startup script
• Outputs the public IP of the VM

🔧 Requirements

• Terraform v1.3+
• GCP credentials configured via gcloud auth application-default login

🚀 How to Use

1. Clone the repo:

git clone <this-repo>
cd terraform-gcp-vm

2. Initialize Terraform:

terraform init

3. Set variables and apply:

terraform apply -var="project_id=your-gcp-project-id" -var="region=us-central1"

4. After ~30 seconds, you’ll see:

Outputs:
vm_public_ip = "X.X.X.X"

5. Visit the VM IP in your browser:

http://X.X.X.X → Should show NGINX welcome page

🧪 Testing

To test:

• Use terraform plan to verify
• Use terraform destroy to clean up after testing

📝 Notes

• Default network is used; ensure "Allow HTTP traffic" is enabled in firewall
• Add SSH access or use IAP as needed

🧪 Terratest (Integration Testing)

To run the integration test using Terratest:

🔧 Requirements

• Go 1.21+
• Terraform installed
• GCP credentials set up (gcloud auth application-default login)

▶️ Run Test

cd test
go mod tidy
go test -v

This will be expected to provision a VM, verify NGINX is running, then destroy the VM.

🚀 Further Improvements

• Use Service Account for Authentication

  • Replace reliance on gcloud auth application-default login with a dedicated service account key to improve portability and CI/CD support.

• Test Enhancements

  • Improve test stability by:
    • Adding exponential backoff and retry logic
    • Making NGINX content check more flexible (use regex or header check)
    • Validating instance metadata via gcloud or GCP APIs

• Expose More Config Options

  • Add optional inputs for:
    • Tags, labels, metadata
    • Disk size/type
    • Custom startup script

• Support Multiple Instances

  • Extend the module to provision a group of VMs using count or for_each.

• Add Outputs for Internal IP, Status, and SSH Command

  • Provide more useful output for users to interact with the VM.