terraform-example-basic

Terraform example

This folder contains an example of how define infrastructure-as-code using Terraform. The Terraform templates in this folder are the "Hello, World" of Terraform, showing how to create a single EC2 instance.

Quick start

Note: these Terraform templates create real resources in your AWS account. The resources are part of the AWS Free Tier, but if you've used up all your credits, they may cost you money.

1. Install Terraform.
2. Add your AWS credentials as the environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY.
3. Run terraform plan.
4. If the plan looks good, run terraform apply.

Making changes

Try making some changes to the template to learn about basic Terraform features, as described in the following sections.

Use a variable

Variables make your templates configurable. To become familiar with variables, try defining one in main.tf:

variable "name" {
  description = "The name of the EC2 instance"
}

Next, use that variable in the tags of the aws_instance:

resource "aws_instance" "example" {
  // ...

  tags {
    Name = "${var.name}"
  }
}

Try running terraform plan and terraform apply to see what happens.

Use dependencies

Terraform resources can depend on each other. Terraform will automatically build a dependency graph and ensure the resources get created in the right order. For example, to add an IP address to the EC2 instance, you can define an aws_eip resource:

resource "aws_eip" "example" {
  instance = "${aws_instance.example.id}"
}

Notice how the instance parameter is set to "${aws_instance.example.id}". This is dependency on the id attribute of the aws_instance you've already created. Terraform now knows that when you apply these templates, it needs to create the aws_instance first, pull out its id, and then it can create the aws_eip.

Cleaning up

To clean up the resources created by these templates, just run terraform destroy.