AWS Terraform Basic Guide: EC2 & RDS

This guide provides a fundamental introduction to using Terraform for provisioning Amazon EC2 instances and Amazon RDS databases. It covers the basic setup, directory structure, and essential Terraform configurations to get you started with Infrastructure as Code on AWS.

1. Prerequisites

Before you begin, ensure you have the following:

• AWS Account with appropriate IAM permissions: Your AWS Identity and Access Management (IAM) user or role must have permissions to create, modify, and delete resources related to EC2, RDS, VPC, and IAM. This includes actions like ec2:*, rds:*, vpc:*, and iam:*.
• Terraform installed (v1.0+ recommended):
  • If you don't have Terraform installed, follow the official installation guide for your operating system.
• AWS CLI configured: Ensure your AWS Command Line Interface (CLI) is configured with your credentials (e.g., by running aws configure) or that your AWS credentials are set via environment variables. Terraform uses these credentials to authenticate with your AWS account.
• Basic understanding of Terraform HCL: Familiarity with HashiCorp Configuration Language (HCL), the language used by Terraform, will be beneficial.

2. Directory & File Structure

It's good practice to organize your Terraform configurations into a clear directory structure. For this basic guide, we'll use a simple layout:

aws-terraform-basics/
│
├── main.tf           # Defines the main AWS resources (VPC, EC2, RDS, Security Group)
├── variables.tf      # Declares input variables for your configurations
├── outputs.tf        # Defines output values that can be easily retrieved after deployment
├── provider.tf       # Configures the AWS provider
└── .terraform/       # (Automatically created by `terraform init`) Stores provider plugins and modules

3. provider.tf

This file configures the AWS provider, telling Terraform which cloud provider to interact with and in which region.

provider "aws" {
  region = var.aws_region # Uses the 'aws_region' variable defined in variables.tf
}

4. variables.tf

This file declares the input variables that allow you to parameterize your Terraform configurations, making them more flexible and reusable.

variable "aws_region" {
  description = "The AWS region where resources will be deployed."
  type        = string
  default     = "ap-southeast-2" # Default region set to Sydney
}

variable "instance_type" {
  description = "The EC2 instance type."
  type        = string
  default     = "t3.micro" # Default instance type
}

variable "db_username" {
  description = "The master username for the RDS database."
  type        = string
  default     = "admin"
}

variable "db_password" {
  description = "The master password for the RDS admin user."
  type        = string
  sensitive   = true # Marks the variable as sensitive to prevent it from being shown in logs/outputs
}

5. main.tf

This is the core configuration file where you define your AWS resources.

VPC & Networking (for demo purposes, simplified)