GCP Multi-Tier Application Infrastructure

---

🚀 Project Overview

This project delivers a production-grade, modular Infrastructure as Code (IaC) solution for deploying a secure, scalable, and highly available multi-tier application on Google Cloud Platform using Terraform. It demonstrates best practices in cloud architecture, automation, and security—making it ideal for real-world enterprise workloads and a strong showcase for recruiters and technical reviewers.

---

🏗️ Architecture Overview

The infrastructure is designed for reliability, scalability, and security:

• Custom VPC with segmented subnets for frontend, application, and database tiers
• Managed Instance Groups for each tier, using startup scripts for automation
• Global HTTP(S) Load Balancer for high availability and traffic distribution
• Fine-grained Firewall Rules and IAM bindings for robust security
• Cloud NAT for secure internet access from private subnets

Architecture Diagram:

---

📁 Project Structure

gcp-multitier-app/
├── architecture/                # Architecture diagrams
│   └── architecture.jpg
├── screenshots/                 # Step-by-step implementation screenshots
│   ├── 01_github_authentication.png
│   ├── 02_github_repo_cloning_tf_scripts.png
│   └── ...
├── modules/                     # Terraform modules (compute, network, loadbalancer, security)
├── scripts/                     # Startup scripts for each tier
├── main.tf                      # Root Terraform configuration
├── variables.tf                 # Input variables
├── outputs.tf                   # Output values
├── providers.tf                 # Provider configuration
├── backend.tf                   # Remote state backend
├── terraform.tfvars             # Variable values for deployment
└── README.md                    # Project documentation

---

📸 Implementation Walkthrough

Each step of the project is documented with screenshots and concise explanations:

1️⃣ GitHub Authentication in gcloud CLI

• Purpose: Secure authentication for CI/CD and cloud automation.

2️⃣ Cloning Terraform Scripts from GitHub

• Purpose: Version control and reproducibility.

3️⃣ Configuring Variables and Self Links

• Purpose: Parameterization for flexible deployments.

4️⃣ Creating Bucket for Terraform State Files

• Purpose: Remote state management for team collaboration.

5️⃣ Initializing Terraform

• Purpose: Provider and backend initialization.

6️⃣ Enabling Required APIs

• Purpose: API enablement for resource provisioning.

7️⃣ Running VM Instances

• Purpose: Automated compute provisioning with Managed Instance Groups.

8️⃣ Custom Firewall Rules

• Purpose: Secure, least-privilege network access.

9️⃣ NIC Network Analysis

• Purpose: Network segmentation and security validation.

🔟 Instance Network Topology

• Purpose: Visualizing and verifying instance connectivity.

1️⃣1️⃣ Frontend Load Balancer Topology

• Purpose: High availability and traffic distribution.

1️⃣2️⃣ NIC Connectivity Test: Frontend to App

• Purpose: Verifying secure, functional inter-tier connectivity.

---

⚡ Quick Start

1. Clone the repository

   git clone <repo-url>
   cd gcp-multitier-app

2. Configure variables
   • Edit terraform.tfvars for your project and network settings.
3. Initialize Terraform

   terraform init

4. Plan the deployment

   terraform plan

5. Apply the configuration

   terraform apply

6. Access the Application
   • The output will display the load balancer's external IP. Open it in your browser.

---

🔍 Verification Commands

• Check VPCs and Subnets

  gcloud compute networks list
  gcloud compute networks subnets list

• Check Compute Instances

  gcloud compute instances list

• Check Firewall Rules

  gcloud compute firewall-rules list

• Check IAM Permissions

  gcloud projects get-iam-policy <YOUR_PROJECT_ID>

---

🧹 Clean Up

To destroy all resources:

terraform destroy

---

🤝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

---

📝 License

This project is licensed under the MIT License. See the LICENSE file for details.

---

🆘 Support

If you encounter any issues or have questions:

• Check the Issues page
• Review the documentation
• Create a new issue with detailed information

---

Note: All screenshots and architecture diagrams are for documentation and demonstration purposes. For actual infrastructure deployment, use the provided Terraform modules and scripts.