Module inputs (variables) in Terraform - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Terraform module variable defaults

Given a Terraform module with a variable defined as variable "region" { default = "us-west-1" }, what will be the value of var.region inside the module if the caller does NOT provide a value?

A "us-west-1"

B null

C An error occurs because the variable is not set

D "us-east-1"

💡 Hint

Think about what happens when a variable has a default value and no override is given.

If a variable has a default value and the caller does not provide a value, Terraform uses the default inside the module.

❓ Configuration

intermediate

Passing variables to a Terraform module

You have a Terraform module that expects a variable instance_count. Which of the following is the correct way to pass the value 3 to this variable when calling the module?

Terraform

module "webserver" {
  source = "./modules/webserver"
  // fill in here
}

A set instance_count 3

B instance_count = 3

C var.instance_count = 3

D variable "instance_count" = 3

💡 Hint

Remember how to assign values to module inputs in the module block.

Inside the module block, you assign values to variables by using variable_name = value syntax.

❓ Architecture

advanced

Variable type constraints in Terraform modules

A module variable is defined as variable "tags" { type = map(string) }. Which of the following values passed to this variable will cause a Terraform plan error?

A {}

B { "Environment" = "prod", "Owner" = "team-a" }

C { Environment = "prod", Owner = "team-a" }

D ["prod", "team-a"]

💡 Hint

Consider the expected type and what each option represents.

The variable expects a map of strings. Option D is a list, not a map, so it causes a type error.

❓ security

advanced

Sensitive variables in Terraform modules

You want to pass a password to a Terraform module variable without showing it in logs or state files. Which variable attribute should you use inside the module to mark it as sensitive?

A sensitive = true

B hidden = true

C private = true

D secure = true

💡 Hint

Terraform has a specific attribute to mark variables as sensitive.

The 'sensitive = true' attribute marks variables so their values are not shown in logs or UI.

❓ service_behavior

expert

Effect of missing required module variables

A Terraform module defines a variable project_id without a default value. The caller does NOT provide a value for this variable. What happens when you run terraform apply?

A Terraform fails with an error about the missing variable

B Terraform applies using a null value for the variable

C Terraform prompts for the missing variable value before applying

D Terraform applies with an empty string as the variable value

💡 Hint

Think about how Terraform handles required variables without defaults and no input.

Terraform will prompt the user to enter a value for required variables without defaults before applying.