Variable declaration syntax in Terraform - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic syntax to declare a variable in Terraform?

Use the variable block with a name and optional attributes like type, default, and description.<br><br>Example:<br>

variable "region" {<br>  type = string<br>  default = "us-west-1"<br>  description = "AWS region to deploy resources"<br>}

beginner

What does the default attribute do in a Terraform variable declaration?

It sets a value that Terraform uses if no other value is provided when running.<br><br>This makes the variable optional because it has a fallback value.

intermediate

How do you specify the type of a variable in Terraform?

Use the type attribute inside the variable block.<br><br>Common types: string, number, bool, list(string), map(string).<br><br>Example:<br>

variable "ports" {<br>  type = list(number)<br>}

beginner

Can you declare a variable without a default value in Terraform? What happens then?

Yes, you can declare a variable without a default.<br><br>Terraform will require you to provide a value when you run your configuration, or it will show an error.

beginner

How do you add a description to a Terraform variable and why is it useful?

Use the description attribute inside the variable block.<br><br>This helps others (and yourself) understand what the variable is for.<br><br>Example:<br>

variable "env" {<br>  type = string<br>  description = "The environment to deploy to, e.g., dev or prod"<br>}

Which block is used to declare a variable in Terraform?

A variable

B resource

C output

D provider

The variable block is used to declare variables in Terraform.

What happens if you declare a variable without a default value and do not provide a value when running Terraform?

A Terraform uses a random value

B Terraform uses an empty string

C Terraform throws an error and stops

D Terraform ignores the variable

Terraform requires a value for variables without defaults; otherwise, it throws an error.

How do you specify that a variable should be a list of strings?

A type = string[]

B type = list(string)

C type = array

D type = map(string)

Terraform uses list(string) to specify a list of strings.

Which attribute is used to provide a fallback value for a variable?

A value

B initial

C fallback

D default

The default attribute sets a fallback value for a variable.

Why is adding a description to a variable useful?

A It documents the variable's purpose

B It changes the variable's value

C It makes the variable required

D It encrypts the variable

Descriptions help explain the purpose of variables to users.

Explain how to declare a variable in Terraform including type, default, and description.

Think about the structure of a variable block and what each attribute does.

What happens if you declare a variable without a default and do not provide a value when running Terraform?

Consider Terraform's behavior when required inputs are missing.