Conditional expressions (ternary) in Terraform - Mini Project: Build & Apply

Using Conditional Expressions (Ternary) in Terraform

📖 Scenario: You are setting up a Terraform configuration to deploy cloud resources. You want to control the size of a virtual machine based on an environment variable. If the environment is 'production', the VM should be large; otherwise, it should be small.

🎯 Goal: Build a Terraform configuration that uses a conditional expression (ternary) to set the VM size based on the environment variable.

📋 What You'll Learn

Create a variable called environment with default value 'development'.

Create a local variable called vm_size that uses a conditional expression to set 'large' if environment is 'production', else 'small'.

Create a resource block for a virtual machine that uses the vm_size local variable.

Ensure the configuration is valid Terraform syntax.

💡 Why This Matters

🌍 Real World

Conditional expressions help automate infrastructure decisions based on environment or other inputs, making deployments flexible and reusable.

💼 Career

Cloud engineers often use Terraform conditionals to manage different deployment environments efficiently.

1

Define the environment variable

Create a Terraform variable called environment with type string and default value "development".

Terraform

# Your code here

Need a hint?

Use the variable block with type and default attributes.

2

Create a local variable vm_size with a conditional expression

Add a locals block and inside it create a local variable called vm_size that uses a conditional expression: if var.environment equals "production", set vm_size to "large", else set it to "small".

Terraform

variable "environment" {
  type    = string
  default = "development"
}

# Your code here

Need a hint?

Use the syntax condition ? true_value : false_value inside the locals block.

3

Create a resource using the vm_size local variable

Add a resource block named aws_instance with resource name example. Set the instance_type attribute to use the local variable local.vm_size. Use ami attribute with a placeholder value "ami-12345678".

Terraform

variable "environment" {
  type    = string
  default = "development"
}

locals {
  vm_size = var.environment == "production" ? "large" : "small"
}

# Your code here

Need a hint?

Use the resource block with the correct resource type and name. Reference the local variable with local.vm_size.

4

Add a provider block for AWS

Add a provider block for aws with region set to "us-east-1".

Terraform

variable "environment" {
  type    = string
  default = "development"
}

locals {
  vm_size = var.environment == "production" ? "large" : "small"
}

resource "aws_instance" "example" {
  ami           = "ami-12345678"
  instance_type = local.vm_size
}

# Your code here

Need a hint?

The provider block tells Terraform which cloud provider to use and the region.