Arguments and expressions in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign the region argument in the provider block.

Terraform

provider "aws" {
  region = "[1]"
}

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

Aus-west-2

Btrue

C123

Dmy-region

Attempts:

3 left

💡 Hint

Common Mistakes

Using boolean or numeric values instead of a region string.

Using an invalid region name.

The region argument expects a valid AWS region string like us-west-2.

2fill in blank

medium

Complete the code to set the instance type argument for the AWS EC2 resource.

Terraform

resource "aws_instance" "example" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "[1]"
}

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

A123

Bt2.micro

Ctrue

Dmy-instance

Attempts:

3 left

💡 Hint

Common Mistakes

Using boolean or numeric values instead of a valid instance type string.

Using an invalid instance type.

The instance_type argument requires a valid EC2 instance type string like t2.micro.

3fill in blank

hard

Fix the error in the expression to correctly reference the variable 'environment'.

Terraform

variable "environment" {
  type = string
}

resource "aws_s3_bucket" "bucket" {
  bucket = "my-app-[1]"
  acl    = "private"
}

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

Aenvironment

Bvar.environment

C${environment}

D${var.environment}

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable name without interpolation syntax.

Using interpolation without the 'var.' prefix.

In Terraform, to use a variable inside a string, you must use interpolation syntax like ${var.environment}.

4fill in blank

hard

Fill both blanks to create a map variable with keys 'dev' and 'prod' and their respective CIDR blocks.

Terraform

variable "cidr_blocks" {
  type = map(string)
  default = {
    dev  = "[1]"
    prod = "[2]"
  }
}

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

A"10.0.1.0/24"

B"10.0.0.0/16"

C"10.0.2.0/24"

D"10.0.3.0/24"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same CIDR block for both environments.

Not using quotes around CIDR strings.

The map variable defines CIDR blocks for 'dev' and 'prod'. Here, 'dev' uses '10.0.1.0/24' and 'prod' uses '10.0.2.0/24'.

5fill in blank

hard

Fill all three blanks to create a resource with a tag key 'Name' and value from a variable, and enable versioning.

Terraform

resource "aws_s3_bucket" "example" {
  bucket = "my-bucket"

  tags = {
    Name = [1]
  }

  versioning {
    enabled = [2]
  }

  lifecycle_rule {
    id      = "log"
    enabled = [3]
  }
}

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

A"var.bucket_name"

Btrue

Cfalse

Dvar.bucket_name

Attempts:

3 left

💡 Hint

Common Mistakes

Putting variable references inside quotes, making them literal strings.

Using string 'true' instead of boolean true.

The tag value should be the variable var.bucket_name without quotes to reference it. Versioning and lifecycle rule 'enabled' flags are booleans set to true.

Practice

1. What is the purpose of arguments inside a Terraform resource block?

easy

A. To set specific details or properties for the resource

B. To run commands on the resource after creation

C. To define the cloud provider used

D. To store output values from the resource

Solution

1. Step 1: Understand resource blocks

   Resource blocks define cloud resources, and arguments inside them specify details like size or name.

2. Step 2: Identify argument role

   Arguments set the properties that Terraform uses to create or manage the resource.

3. Final Answer:

   To set specific details or properties for the resource -> Option A

4. Quick Check:

   Arguments = resource details [OK]

Hint: Arguments define resource details inside blocks [OK]

Common Mistakes:

• Confusing arguments with outputs
• Thinking arguments run commands
• Mixing provider definition with arguments

2. Which of the following is the correct syntax to assign a variable value to an argument in Terraform?

easy

A. name := var.instance_name

B. name => var.instance_name

C. name == var.instance_name

D. name = var.instance_name

Solution

1. Step 1: Recall Terraform assignment syntax

   Terraform uses single equals sign (=) to assign values to arguments.

2. Step 2: Match variable usage

   Variables are referenced with var.<variable_name> and assigned using =.

3. Final Answer:

   name = var.instance_name -> Option D

4. Quick Check:

   Assignment uses = and var. prefix [OK]

Hint: Use = to assign variables in Terraform [OK]

Common Mistakes:

• Using := or == instead of =
• Confusing arrow => with assignment
• Omitting var. prefix for variables

3. Given the Terraform expression count = var.enable ? 3 : 1 and var.enable = false, what will be the value of count?

medium

A. true

B. 3

C. 1

D. false

Solution

1. Step 1: Understand the ternary expression

   The expression uses a condition: if var.enable is true, count is 3; else count is 1.

2. Step 2: Substitute variable value

   Since var.enable is false, the expression returns the value after the colon, which is 1.

3. Final Answer:

   1 -> Option C

4. Quick Check:

   False condition returns second value [OK]

Hint: Ternary returns value after colon if condition is false [OK]

Common Mistakes:

• Choosing the first value regardless of condition
• Confusing boolean with numeric output
• Ignoring variable value in expression

4. What is wrong with this Terraform argument expression?

size = var.instance_size ? "large" : "small"

assuming var.instance_size is a string variable.

medium

A. Ternary condition requires a boolean, not a string

B. Strings cannot be used in ternary expressions

C. The quotes around "large" and "small" are invalid

D. Variable names cannot be used in expressions

Solution

1. Step 1: Check ternary condition type

   The condition before ? must be boolean (true/false), but var.instance_size is a string.

2. Step 2: Identify type mismatch error

   Using a string as condition causes an error because Terraform expects a boolean expression.

3. Final Answer:

   Ternary condition requires a boolean, not a string -> Option A

4. Quick Check:

   Condition must be boolean [OK]

Hint: Ternary condition must be true/false, not string [OK]

Common Mistakes:

• Using strings as conditions
• Misplacing quotes around values
• Assuming variables can't be in expressions

5. You want to create multiple AWS EC2 instances only if var.create_instances is true. Which expression correctly sets the count argument to 5 when true, or 0 when false?

hard

A. count = var.create_instances == 5

B. count = var.create_instances ? 5 : 0

C. count = var.create_instances && 5

D. count = var.create_instances || 0

Solution

1. Step 1: Understand conditional count setting

   We want count to be 5 if var.create_instances is true, else 0.

2. Step 2: Evaluate each option

   count = var.create_instances ? 5 : 0 uses ternary: if true, 5; else 0. Options B, C, D misuse operators or return booleans.

3. Final Answer:

   count = var.create_instances ? 5 : 0 -> Option B

4. Quick Check:

   Ternary sets count correctly [OK]

Hint: Use ternary to set count based on boolean variable [OK]

Common Mistakes:

• Using boolean expressions instead of numbers for count
• Confusing && and || operators for count
• Not using ternary for conditional count