Arguments and expressions in Terraform - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an argument in Terraform?

An argument in Terraform is a key-value pair inside a resource or module block that sets a specific property or configuration.

beginner

What is an expression in Terraform?

An expression in Terraform is a combination of values, variables, functions, or operators that Terraform evaluates to produce a result.

beginner

How do you use variables inside arguments in Terraform?

You use variables inside arguments by referencing them with syntax like ${var.variable_name} or simply var.variable_name in newer versions.

intermediate

What does this expression do?

count = var.enable ? 1 : 0

This expression uses a condition to set count to 1 if var.enable is true, otherwise 0. It controls resource creation based on a variable.

intermediate

Why are expressions useful in Terraform arguments?

Expressions let you create dynamic and flexible configurations by calculating values, using conditions, or referencing variables and outputs.

In Terraform, what is an argument?

A A key-value pair inside a resource block

B A function that runs during deployment

C A type of variable

D A command line option

Arguments are key-value pairs inside resource or module blocks that set properties.

Which of the following is a valid Terraform expression?

A resource.aws_instance

B var.instance_count + 2

C terraform apply

D module.network

Expressions combine values and variables, like adding numbers.

How do you reference a variable named 'region' in Terraform 0.12+?

A region

B ${var.region}

C var.region

D variable.region

In Terraform 0.12 and later, you can reference variables directly as var.region.

What does this expression do?

enabled = var.is_active && var.has_permission

A Sets enabled to true only if both variables are true

B Sets enabled to true if either variable is true

C Sets enabled to false always

D Throws an error

The && operator means both conditions must be true for enabled to be true.

Why use expressions in Terraform arguments?

A To hardcode values

B To write comments

C To run scripts

D To create dynamic and flexible configurations

Expressions allow dynamic values based on variables and conditions.

Explain what arguments and expressions are in Terraform and how they work together.

Think about how you set properties and use variables or conditions.

Describe a simple example where you use an expression inside an argument to control resource creation.

Consider how to create or skip a resource based on a variable.