Why variables make configurations reusable in Terraform - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable for the AWS region.

Terraform

variable "region" {
  type = [1]
}

Drag options to blanks, or click blank then click option'

Anumber

Bstring

Cbool

Dlist

Attempts:

3 left

💡 Hint

Common Mistakes

Using number or bool as the variable type for region.

The variable type for AWS region should be string because regions are text values.

2fill in blank

medium

Complete the code to assign a default value to the variable.

Terraform

variable "instance_type" {
  type    = string
  default = [1]
}

Drag options to blanks, or click blank then click option'

A"t2.micro"

Bt2.micro

Ct2_micro

Dmicro

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes around the default string value.

The default value must be a string literal, so it needs quotes: "t2.micro".

3fill in blank

hard

Fix the error in referencing the variable in the resource block.

Terraform

resource "aws_instance" "example" {
  ami           = "ami-123456"
  instance_type = [1]
}

Drag options to blanks, or click blank then click option'

Avariable.instance_type

Binstance_type

Cvar.instance_type

Dvar[instance_type]

Attempts:

3 left

💡 Hint

Common Mistakes

Using the variable name without var. prefix.

Using incorrect syntax like variable.instance_type.

To use a variable in Terraform, prefix it with var. like var.instance_type.

4fill in blank

hard

Fill both blanks to define a variable with a description and a default value.

Terraform

variable "environment" {
  description = [1]
  default     = [2]
}

Drag options to blanks, or click blank then click option'

A"The deployment environment"

Bproduction

C"production"

D"Deployment environment"

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes for description or default value.

Using unquoted default values.

The description must be a quoted string, and the default value must also be a quoted string.

5fill in blank

hard

Fill all three blanks to use variables for region, instance type, and count in the resource.

Terraform

resource "aws_instance" "web" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = [1]
  count         = [2]
  availability_zone = [3]
}

Drag options to blanks, or click blank then click option'

Avar.instance_type

Bvar.count

Cvar.region

Dvar.availability_zone

Attempts:

3 left

💡 Hint

Common Mistakes

Using var.region for availability zone.

Not using var. prefix.

Use var.instance_type for instance type, var.count for count, and var.availability_zone for availability zone variables.

Practice

1. Why do variables make Terraform configurations reusable?

easy

A. Because they allow changing values without modifying the main code

B. Because they automatically create resources

C. Because they prevent any errors in the code

D. Because they remove the need for providers

Solution

1. Step 1: Understand the role of variables

   Variables hold values that can be changed without editing the main configuration code.

2. Step 2: Recognize how this affects reusability

   Changing variable values lets you reuse the same code for different setups or environments easily.

3. Final Answer:

   Because they allow changing values without modifying the main code -> Option A

4. Quick Check:

   Variables = flexible values [OK]

Hint: Variables let you change inputs, not code [OK]

Common Mistakes:

• Thinking variables create resources automatically
• Believing variables fix all code errors
• Assuming variables replace providers

2. Which of the following is the correct way to declare a variable in Terraform?

easy

A. var region = "us-west-1"

B. variable "region" { default = "us-west-1" }

C. set variable region = "us-west-1"

D. define region: "us-west-1"

Solution

1. Step 1: Recall Terraform variable syntax

   Terraform variables are declared using the keyword 'variable' followed by the name in quotes and a block with settings.

2. Step 2: Match the syntax to options

   variable "region" { default = "us-west-1" } matches the correct syntax: variable "region" { default = "us-west-1" }.

3. Final Answer:

   variable "region" { default = "us-west-1" } -> Option B

4. Quick Check:

   Correct variable syntax = variable "region" { default = "us-west-1" } [OK]

Hint: Look for 'variable' keyword and braces {} [OK]

Common Mistakes:

• Using 'var' keyword incorrectly
• Missing braces {} around variable block
• Using assignment syntax from other languages

3. Given this Terraform snippet:

variable "instance_type" { default = "t2.micro" }
resource "aws_instance" "web" {
  ami           = "ami-123456"
  instance_type = var.instance_type
}

What will be the instance type if no variable value is provided?

medium

A. t2.micro

B. ami-123456

C. var.instance_type

D. No instance type will be set

Solution

1. Step 1: Identify the default variable value

   The variable "instance_type" has a default value set to "t2.micro".

2. Step 2: Understand variable usage in resource

   The resource uses var.instance_type, so if no override is given, it uses the default "t2.micro".

3. Final Answer:

   t2.micro -> Option A

4. Quick Check:

   Default variable value used = t2.micro [OK]

Hint: Default value applies if no override given [OK]

Common Mistakes:

• Confusing AMI ID with instance type
• Thinking var.instance_type is a string literal
• Assuming no value means no instance type

4. You wrote this variable declaration:

variable "env" = "production"

Why does Terraform give an error?

medium

A. Because default values must be numbers

B. Because variable names cannot be "env"

C. Because variable declarations need a block, not an assignment

D. Because variables cannot have default values

Solution

1. Step 1: Check variable declaration syntax

   Terraform variables must be declared using a block: variable "name" { ... } not with '=' assignment.

2. Step 2: Identify the error cause

   Using '=' directly after variable name causes syntax error.

3. Final Answer:

   Because variable declarations need a block, not an assignment -> Option C

4. Quick Check:

   Variable declaration requires block syntax [OK]

Hint: Use braces {} for variables, not '=' [OK]

Common Mistakes:

• Using '=' instead of block for variables
• Thinking variable names are restricted
• Believing default values must be numeric

5. You want to reuse a Terraform module for multiple environments (dev, test, prod) with different instance sizes. How do variables help achieve this?

hard

A. By writing separate code for each environment without variables

B. By using variables only for provider configuration

C. By hardcoding instance sizes inside the module

D. By defining a variable for instance size and passing different values per environment

Solution

1. Step 1: Understand module reuse with variables

   Variables let you set inputs like instance size dynamically when calling the module.

2. Step 2: Apply different values per environment

   Passing different values for the instance size variable lets the same module create resources tailored to each environment.

3. Final Answer:

   By defining a variable for instance size and passing different values per environment -> Option D

4. Quick Check:

   Variables enable flexible module inputs [OK]

Hint: Use variables to customize modules per environment [OK]

Common Mistakes:

• Duplicating code instead of using variables
• Hardcoding values inside modules
• Limiting variables to provider settings only