Terraform Infrastructure Documentation

Architecture Diagram

The following diagram illustrates the overall AWS infrastructure provisioned by this Terraform project:

This diagram shows the relationships between the VPC, subnets, route tables, security groups, EC2 webserver host, and RDS instance, providing a visual overview of the deployed resources.

This folder contains the Terraform code for provisioning a secure, highly-available AWS infrastructure, including VPC, subnets, security groups, EC2 webserver, RDS, and supporting resources. The code is modular and reusable, following best practices for infrastructure-as-code.

Structure

scripts/

• bootstrap.sh: Contains webserser instance user data to run at the launch of the instance.

terraform/

• main.tf: Orchestrates the infrastructure by calling modules for VPC, subnets, route tables, security groups, EC2, and RDS.
• provider.tf: Configures the AWS provider and required provider versions.
• backend_s3.tf: Configures remote state storage in an S3 bucket for collaboration and state locking.
• output.tf: Exposes key outputs such as VPC ID, subnet IDs, route table IDs, EC2 instance ID, and security group IDs.
• terraform.auto.tfvars: Supplies actual values for input variables (e.g., environment name, DB engine, credentials).
• variable: Declares all input variables used across modules.
• local.tf: Defines local values used for cleaner expressions and consistent naming conventions.
• source modules: Contains reusable predefined modules for each infrastructure component from a github repo

Module Details

VPC Module

• Provisions a VPC with configurable CIDR, DNS support, and tags.

Subnets Module

• Creates multiple subnets (public/private) in specified AZs, with options for public IP mapping.

S3

• Creates a secure, versioned S3 bucket for storing VPC Flow Logs, with encryption, public access blocking, lifecycle rules for cost optimization, and an IAM role/policy to allow VPC Flow Logs to write to the bucket.

Internet Gateway Module

• Attaches an Internet Gateway to the VPC for public subnet internet access.

Route Tables Module

• Creates and associates route tables for public/private subnets, supporting both IGW and NAT Gateway routing.

instance Module

• Deploys an EC2 instance in a public subnet for secure SSH access, using a specified key pair and security group. Contains a scripts folder for the setup the webserver

RDS Module

• Provisions an RDS instance with:
  • DB subnet group
  • Configurable engine, version, storage, and instance class

Security Group Modules

• Creates security groups for public and private resources, with dynamic ingress/egress rules.

SSM_Parameter modules

• Generates random RDS credentials and stores them, along with DB config values, in AWS SSM Parameter Store for secure access.

Iam_role modules

• Creates an IAM role and instance profile for EC2 to securely access SSM Parameter Store and retrieve database credentials.

Remote State

• State is stored in an S3 bucket (infra-terraform-backend-database-rds) with locking enabled for safe collaboration.

Usage

1. Initialize Terraform

   terraform init
   

2. format the argument

   terraform fmt
   

3. validate the argument

   terraform validate
   

4. plan the deployment

   terraform plan
   

5. Apply the configuration

   terraform apply
   

Webserver view

Notes

• All sensitive credentials (RDS username/password) are stored securely in AWS SSM Parameter Store.
• Update variable values as needed in each module for your environment.
• Ensure your AWS credentials and region are configured before running Terraform.