Exercise 1: Your First Terraform Configuration (AWS)

Objective

Learn how to create a basic Terraform configuration to deploy AWS infrastructure. This exercise will help you understand the core Terraform workflow with AWS resources.

Prerequisites

AWS Authentication

You have two options for AWS authentication:

  1. AWS CLI Configuration:
    • Install and configure the AWS CLI using aws configure
    • Terraform will automatically use these credentials
  2. Explicit Credentials in Terraform:
    • Set environment variables: 
      export AWS_ACCESS_KEY_ID="your_access_key"
export AWS_SECRET_ACCESS_KEY="your_secret_key"
export AWS_REGION="us-east-1"
    • Or specify directly in the provider (not recommended for production): 
      provider "aws" {
  region     = "us-east-1"
  access_key = "your_access_key"
  secret_key = "your_secret_key"
}

Instructions

Step 1: Create the Configuration Files

Create a new directory for this exercise and navigate to it:

mkdir -p terraform-exercises/01-first-config
cd terraform-exercises/01-first-config

Create the following files:

  1. main.tf - Main configuration file
# Configure the AWS Provider
provider "aws" {
  region = "us-east-1"
}

# Create a VPC
resource "aws_vpc" "main" {
  cidr_block = "10.0.0.0/16"
  
  tags = {
    Name = "main-vpc"
    Environment = "Learning"
    CreatedBy = "Terraform"
  }
}

# Create a subnet within the VPC
resource "aws_subnet" "main" {
  vpc_id     = aws_vpc.main.id
  cidr_block = "10.0.1.0/24"
  
  tags = {
    Name = "main-subnet"
  }
}

# Create a security group
resource "aws_security_group" "allow_ssh" {
  name        = "allow_ssh"
  description = "Allow SSH inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "SSH from anywhere"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    Name = "allow_ssh"
  }
}
  1. outputs.tf - Define outputs
output "vpc_id" {
  description = "The ID of the VPC"
  value       = aws_vpc.main.id
}

output "subnet_id" {
  description = "The ID of the subnet"
  value       = aws_subnet.main.id
}

output "security_group_id" {
  description = "The ID of the security group"
  value       = aws_security_group.allow_ssh.id
}
  1. versions.tf - Define provider versions
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
  
  required_version = ">= 1.0.0"
}

Step 2: Initialize the Working Directory

Run the following command to initialize your working directory:

terraform init

You should see output indicating that Terraform has been successfully initialized and the AWS provider has been installed.

Step 3: Format and Validate the Configuration

Format your configuration files for consistency:

terraform fmt

Validate your configuration syntax:

terraform validate

You should see a message that the configuration is valid.

Step 4: Create an Execution Plan

Generate an execution plan:

terraform plan

Review the execution plan to understand what Terraform will do. You should see that Terraform plans to create 3 resources:

Step 5: Apply the Configuration

Apply the configuration to create the resources:

terraform apply

When prompted, type yes to confirm. Terraform will proceed to create the resources in your AWS account.

After the apply is complete, you should see the output values for the VPC ID, subnet ID, and security group ID.

Step 6: Verify the Created Resources

  1. Log in to the AWS Management Console
  2. Navigate to the VPC service
  3. Confirm that the VPC, subnet, and security group have been created with the specified configuration

Step 7: Examine the State File

Take a look at the state file that Terraform created:

terraform state list

This command shows all the resources in your state file.

To see details of a specific resource:

terraform state show aws_vpc.main

Step 8: Destroy the Resources

When you’re finished, destroy the resources to avoid any ongoing charges:

terraform destroy

When prompted, type yes to confirm.

Additional Challenges

  1. Modify your configuration to add a second subnet in a different availability zone
  2. Add an Internet Gateway resource and attach it to your VPC
  3. Create a Route Table and associate it with your subnets
  4. Use variables to parameterize your configuration (e.g., for the CIDR blocks)

Solution

The solution for this exercise is provided in the solution directory.

Key Learnings