Terraform Modules Repository

A comprehensive collection of reusable Terraform modules for multi-cloud infrastructure provisioning. This repository follows industry best practices and supports multi-region and multi-account deployments.

Supported Providers

• AWS - Amazon Web Services modules
• GCP - Google Cloud Platform modules
• Kubernetes - Kubernetes resource modules

Repository Structure

.
├── aws/
│   ├── vpc/              ✅ Complete - Multi-AZ VPC with NAT Gateway
│   ├── ec2/              🚧 Planned
│   ├── eks/              🚧 Planned
│   ├── sqs/              🚧 Planned
│   ├── event-bus/        🚧 Planned
│   ├── lambda/           🚧 Planned
│   ├── dynamo/           🚧 Planned
│   ├── rds/              🚧 Planned
│   ├── event-rules/      🚧 Planned
│   ├── elasticache/      🚧 Planned
│   ├── ecr/              🚧 Planned
│   ├── parameter-store/  🚧 Planned
│   ├── cloudwatch/       🚧 Planned
│   └── s3/               🚧 Planned
├── gcp/
│   ├── vpc/              ✅ Complete - Global VPC with Cloud NAT
│   ├── cloud-functions/  ✅ Complete - Gen 2 Functions
│   ├── compute-engine/   🚧 Planned
│   ├── gke/              🚧 Planned
│   ├── pubsub/           🚧 Planned
│   ├── cloud-storage/    🚧 Planned
│   └── [Other modules]   🚧 Planned
├── kubernetes/
│   └── [K8s modules]     🚧 Planned
└── TEMPLATES/
    └── module-template   ✅ Complete base template

Available Modules

AWS Modules

Module	Status	Description	Features
vpc	✅ Complete	Multi-AZ VPC with complete networking	Public/private subnets, NAT Gateway, IGW, VPC Flow Logs, VPC Endpoints, Multi-region replication

GCP Modules

Module	Status	Description	Features
vpc	✅ Complete	Global VPC with regional subnets	Cloud NAT, Firewall Rules, VPC Peering, Flow Logs, Secondary IP ranges (GKE), Multi-project replication
cloud-functions	✅ Complete	Serverless functions (Gen 2)	HTTP/Event triggers, VPC Connector, Secret Manager, Auto-scaling, Multi-region replication

Features

• Multi-Region Support - Deploy resources across multiple AWS/GCP regions
• Multi-Account/Multi-Project Support - Cross-account/project resource provisioning
• Replication Patterns - Built-in replication support for stateful services and disaster recovery
• Best Practices - Following Terraform and cloud provider best practices
• Comprehensive Documentation - Each module includes detailed README with examples
• Modern Terraform - Built for Terraform 1.8+ with optional() types and advanced validations

Requirements

• Terraform >= 1.8.0
• Provider-specific CLI tools (aws-cli, gcloud, kubectl)
• Appropriate cloud credentials configured

Usage

Basic Module Usage

module "vpc" {
  source = "./aws/vpc"

  vpc_name    = "production-vpc"
  cidr_block  = "10.0.0.0/16"
  environment = "production"

  tags = {
    Project = "MyProject"
    Team    = "Platform"
  }
}

Multi-Region Deployment

# Primary region
module "s3_primary" {
  source = "./aws/s3"

  bucket_name       = "my-app-data"
  environment       = "production"
  with_replication  = true
  replication_region = "us-west-2"

  providers = {
    aws.primary     = aws.us-east-1
    aws.destination = aws.us-west-2
  }
}

Multi-Account Deployment

# Cross-account setup
module "lambda_cross_account" {
  source = "./aws/lambda"

  function_name           = "cross-account-processor"
  destination_account_id  = "123456789012"

  providers = {
    aws.source      = aws.main-account
    aws.destination = aws.secondary-account
  }
}

Module Standards

All modules in this repository follow these standards:

File Structure

• main.tf - Primary resource definitions
• variables.tf - Input variable declarations with descriptions
• outputs.tf - Output value definitions
• versions.tf - Terraform and provider version constraints
• README.md - Module documentation with examples
• data.tf - (Optional) Data source lookups
• locals.tf - (Optional) Local values and computations
• iam.tf - (Optional) IAM roles and policies
• examples/ - (Optional) Example configurations

Variable Naming Conventions

• enable_* - Boolean flags for feature toggles (e.g., enable_logging)
• with_* - Configuration enablement (e.g., with_replication)
• is_* - State checks (e.g., is_production)
• Use snake_case for all variable names
• Provide descriptions and types for all variables
• Set sensible defaults for optional variables

Tagging Strategy

All modules support consistent tagging:

tags = {
  Name        = "\${var.resource_name}-\${var.environment}"
  Environment = var.environment
  ManagedBy   = "Terraform"
  Module      = "module-name"
}

Testing Modules

Each module can be tested using the examples provided:

cd aws/vpc/examples/basic
terraform init
terraform plan
terraform apply
terraform destroy

Contributing

When creating new modules:

1. Use the templates in TEMPLATES/ as a starting point
2. Follow the module standards outlined above
3. Include comprehensive README.md with:
   • Description
   • Usage examples
   • Input variables table
   • Output values table
   • Requirements
4. Add examples in examples/ directory
5. Test the module before committing
6. Run terraform fmt -recursive to format code

Module Development Workflow

# Create new module from template
cp -r TEMPLATES/module-template aws/new-service

# Develop your module
cd aws/new-service
# Edit main.tf, variables.tf, outputs.tf, etc.

# Format code
terraform fmt -recursive

# Validate
terraform validate

# Test with example
cd examples/basic
terraform init
terraform plan

Version Constraints

All modules specify minimum versions:

terraform {
  required_version = ">= 1.8.0"

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = ">= 5.0"
    }
  }
}

Security Best Practices

• Never commit sensitive data (.tfvars, state files)
• Use AWS Secrets Manager or Parameter Store for secrets
• Enable encryption at rest for all stateful services
• Implement least-privilege IAM policies
• Use private subnets for workloads
• Enable logging and monitoring

Common Patterns

Conditional Resource Creation

resource "aws_s3_bucket" "replica" {
  count = var.with_replication ? 1 : 0
  # ...
}

Dynamic Blocks for Optional Features

dynamic "encryption" {
  for_each = var.enable_encryption ? [1] : []
  content {
    # encryption configuration
  }
}

Tag Merging

locals {
  default_tags = {
    ManagedBy   = "Terraform"
    Environment = var.environment
  }
}

tags = merge(local.default_tags, var.tags)

Support and Documentation

• Terraform AWS Provider: https://registry.terraform.io/providers/hashicorp/aws/latest/docs
• Terraform GCP Provider: https://registry.terraform.io/providers/hashicorp/google/latest/docs
• Terraform Kubernetes Provider: https://registry.terraform.io/providers/hashicorp/kubernetes/latest/docs

License

This repository contains infrastructure code modules for internal use.