Launching EC2 instance with terraform

Author: Duc Thai

Email: ducthai060501@gmail.com

Overview

Today we are going to start working with Terraform!

Here’s what we’re here to do:

• Understand the meaning behind the name:
  "Terraform" originally means “to transform the atmosphere of a planet to make it habitable”—think of science fiction stories where Mars is made livable, or the machines in Superman trying to change Earth.
• Apply that metaphor to cloud computing:
  Instead of planets, we’ll be “terraforming” our AWS (or other cloud) accounts—making the cloud environment more suitable and structured for running our applications.
• Learn about Terraform as a tool:
  Terraform is a tool that helps us define, create, and manage infrastructure (like servers, networks, or databases) in a cloud account in a safe, repeatable, and automated way.

In summary:
We're here to learn how to make our cloud accounts (like AWS) ready for our applications—using Terraform as our tool for automated, codified infrastructure setup.

some intro about terraform

In this step, we are introducing the basics of Terraform’s configuration language and seeing what a typical Terraform file looks like.

What are we doing?

• Exploring the Terraform language:
  • Terraform uses its own, simple configuration syntax that looks similar to JSON (technically, it's HashiCorp Configuration Language, or HCL).
  • You define infrastructure as code using blocks like resource, specify the type (e.g., aws_instance), a resource name (like web01), and then all the required settings (like ami, instance_type, etc.) as arguments.
• Validating and formatting:
  • You can check and format your code using commands like terraform fmt (automatic formatting) and terraform validate (syntax and logical validation).
• Understanding the workflow:
  • Once you write your code, you run Terraform.
  • Terraform will check if the resource (e.g., EC2 instance) already exists—if not, it creates it using the cloud provider’s API.
  • The state and details of what’s created are stored in a special “state file” managed by Terraform, so your infrastructure is tracked.

Summary:
You're learning the fundamental structure of Terraform files, seeing real examples of resource blocks, and understanding how Terraform reads, formats, validates, and manages cloud infrastructure code—keeping everything tracked in its state.

Install terraform and aws set up

In this step, you are setting up your local development environment for using Terraform with AWS. Here’s exactly what you’re doing:

1. Installing Terraform

• Go to the official Terraform installation page.
• Download and install Terraform for your operating system (Windows, macOS, or Linux).

• After installing, run:

  terraform --version

  to confirm Terraform is installed and see the version number.

2. Setting Up AWS CLI

• Make sure the AWS Command Line Interface (CLI) is installed on your machine.

• Run:

  aws configure

  and provide your AWS credentials (Access Key, Secret Key, region, etc.).

• This step lets both the AWS CLI and Terraform authenticate and manage cloud resources in your AWS account.

Summary:
You are preparing your environment by installing Terraform and configuring the AWS CLI so that you can provision and manage AWS resources using Terraform code in later steps.

Let's dive in

Launching EC2 with Terraform

Table of Contents

1. Finding AMI IDs
2. Terraform Basics
3. Basic Commands
4. Running Your First Script
5. Summary

Finding AMI IDs

There are several ways to find Amazon Machine Image (AMI) IDs for your EC2 instances.

Method 1: AWS CLI

Use the AWS CLI command to find the latest Amazon Linux 2 AMI:

aws ec2 describe-images --owners amazon --filters "Name=name,Values=amzn2-ami-hvm-*-x86_64-gp2" --query "reverse(sort_by(Images, &CreationDate))[:1].ImageId" --output text

Method 2: AWS Console

1. Go to EC2 Dashboard
2. Navigate to Images → AMIs
3. Search for "amzn2-ami-hvm-*-x86_64-gp2"

Method 3: Terraform Data Source

Use Terraform data source to get the latest AMI ID dynamically:

data "aws_ami" "amiID" {
  most_recent = true
  
  filter {
    name   = "name"
    values = ["ami-0fa91bc90632c73c9"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["amazon"]
}

Terraform Basics

Data Sources

To get information outside Terraform, we use data sources.

Syntax:

data "TYPE" "NAME" {
  CONFIG
}

Data sources allow you to fetch information from your cloud provider or other external sources.

Output Blocks

Just like print in Python, output blocks are used to display values after terraform apply.

Syntax:

output "output_name" {
  description = "Description of the output"
  value       = resource.type.name.attribute
}

Basic Commands

Here are the essential Terraform commands you need to know:

Command Details

• init: Reads configuration files in the current directory and downloads necessary provider plugins.
• plan: Creates an execution plan, showing what actions Terraform will take to achieve the desired state.
• apply: Applies the changes required to reach the desired state of the configuration.

Running Your First Script

Script Example

Create a file named main.tf with the following content:

data "aws_ami" "amiID" {
  most_recent = true
  
  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-jammy-22.04-amd64-server-*"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["099720109477"] # Canonical
}

output "instance_ami_id" {
  description = "AMI ID of Ubuntu instance"
  value       = data.aws_ami.amiID.id
}

What This Script Does

This script will output the latest Ubuntu 22.04 AMI ID using Terraform data sources.

Running the Commands

Execute the following commands in order:

terraform init
terraform plan
terraform apply

Expected Output

ducth@DucPC MINGW64 ~/git_repos/quicksight-01/code/terraform/ex1 (main)
$ terraform apply
data.aws_ami.amiID: Reading...
data.aws_ami.amiID: Read complete after 0s [id=ami-0c846debef94e83c2]

Changes to Outputs:
  + instance_ami_id = "ami-0c846debef94e83c2"

You can apply this plan to save these new output values to the Terraform state, 
without changing any real infrastructure.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes


Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Outputs:

instance_ami_id = "ami-0c846debef94e83c2"

Summary

Key Takeaways

• Terraform is an infrastructure as code tool that allows you to define and manage cloud resources.
• Basic Commands:init, validate, plan, apply are the core commands for working with Terraform.
• Data Sources are used to fetch information from outside Terraform (like AMI IDs from AWS).
• Output Blocks display values after terraform apply, similar to print statements in programming.
• AMI IDs can be found using AWS CLI, AWS Console, or Terraform data sources for dynamic retrieval.