Default values in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set a default value for the variable.

Terraform

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

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

Aus-west-2

Btrue

C10

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using a boolean or number instead of a string for the default value.

Leaving the default value empty.

The default value for the variable region should be a valid AWS region string like us-west-2.

2fill in blank

medium

Complete the code to set a default value for the variable with a list of strings.

Terraform

variable "availability_zones" {
  type    = list(string)
  default = [1]
}

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

A3

B"us-west-2a"

Ctrue

D["us-west-2a", "us-west-2b"]

Attempts:

3 left

💡 Hint

Common Mistakes

Using a single string instead of a list.

Using a boolean or number instead of a list.

The default value must be a list of strings matching the variable type list(string).

3fill in blank

hard

Fix the error in the variable default value to match the declared type.

Terraform

variable "instance_count" {
  type    = number
  default = [1]
}

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

A[3]

B"3"

C3

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Putting the number inside quotes, making it a string.

Using a list or boolean instead of a number.

The default value must be a number without quotes to match the number type.

4fill in blank

hard

Fill both blanks to define a variable with a map type and default values.

Terraform

variable "tags" {
  type    = map(string)
  default = { [1] = [2] }
}

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

A"Environment"

B"Production"

C"Version"

D"1.0"

Attempts:

3 left

💡 Hint

Common Mistakes

Using unquoted keys or values.

Mixing keys and values incorrectly.

The map key should be a string like "Environment" and the value a string like "Production".

5fill in blank

hard

Fill all three blanks to define a variable with a complex default map of strings.

Terraform

variable "metadata" {
  type    = map(string)
  default = {
    [1] = [2]
    [3] = "v1"
  }
}

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

A"Owner"

B"Alice"

C"Project"

D"CloudInfra"

Attempts:

3 left

💡 Hint

Common Mistakes

Using unquoted keys or values.

Mixing keys and values incorrectly.

The map keys and values must be strings. Here, "Owner" maps to "Alice", and "Project" maps to "v1".

Practice

1. What is the purpose of setting a default value for a variable in Terraform?

easy

A. To make the variable mandatory without a fallback

B. To provide a fallback value if no other value is given

C. To disable the variable completely

D. To automatically generate a random value

Solution

1. Step 1: Understand variable defaults in Terraform

   Default values act as fallback values when no input is provided by the user.

2. Step 2: Identify the purpose of default values

   They make variables optional and provide a safe, predictable value.

3. Final Answer:

   To provide a fallback value if no other value is given -> Option B

4. Quick Check:

   Default value = fallback [OK]

Hint: Default means fallback if no input given [OK]

Common Mistakes:

• Thinking default makes variable mandatory
• Assuming default disables the variable
• Believing default auto-generates random values

2. Which of the following is the correct syntax to set a default value for a variable named region in Terraform?

easy

A. variable "region" { default = "us-east-1" }

B. variable region { default: "us-east-1" }

C. var region = default "us-east-1"

D. variable "region" = "us-east-1"

Solution

1. Step 1: Recall Terraform variable block syntax

   Variables are declared with the keyword variable and a name in quotes.

2. Step 2: Check correct default assignment

   The default value is set inside the block with default = "value".

3. Final Answer:

   variable "region" { default = "us-east-1" } -> Option A

4. Quick Check:

   Correct syntax uses variable block and default = value [OK]

Hint: Use variable "name" { default = "value" } [OK]

Common Mistakes:

• Missing quotes around variable name
• Using colon instead of equals for default
• Assigning default outside variable block

3. Given this variable declaration:

variable "instance_type" {
  default = "t2.micro"
}

What will be the value of var.instance_type if no override is provided?

medium

A. null

B. Error: variable not set

C. empty string ""

D. "t2.micro"

Solution

1. Step 1: Identify the default value in the variable block

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

2. Step 2: Understand behavior when no override is given

   If no value is provided, Terraform uses the default value automatically.

3. Final Answer:

   "t2.micro" -> Option D

4. Quick Check:

   Default used if no override [OK]

Hint: No override? Use default value [OK]

Common Mistakes:

• Assuming null if no value given
• Expecting error without override
• Thinking default is empty string

4. You wrote this variable block:

variable "env" {
  default: "production"
}

Why does Terraform give a syntax error?

medium

A. Because default uses colon instead of equals sign

B. Because variable name must not be in quotes

C. Because default value must be a number

D. Because variable blocks cannot have defaults

Solution

1. Step 1: Check the syntax for default assignment

   Terraform requires = to assign default values, not a colon.

2. Step 2: Identify the cause of syntax error

   Using default: "production" causes a syntax error because colon is invalid here.

3. Final Answer:

   Because default uses colon instead of equals sign -> Option A

4. Quick Check:

   Use = not : for default [OK]

Hint: Use = for default, not colon : [OK]

Common Mistakes:

• Using colon instead of equals for default
• Removing quotes from variable name
• Thinking default must be numeric

5. You want to create a variable availability_zones with a default list of zones ["us-east-1a", "us-east-1b"]. Which is the correct way to declare it in Terraform?

hard

A. variable "availability_zones" {
default = "us-east-1a, us-east-1b"
}

B. variable availability_zones = ["us-east-1a", "us-east-1b"]

C. variable "availability_zones" {
type = list(string)
default = ["us-east-1a", "us-east-1b"]
}

D. variable "availability_zones" {
type = string
default = ["us-east-1a", "us-east-1b"]
}

Solution

1. Step 1: Define variable with correct type for list of strings

   Use type = list(string) to specify a list of strings.

2. Step 2: Assign default as a list of strings

   Set default = ["us-east-1a", "us-east-1b"] inside the variable block.

3. Final Answer:

   variable "availability_zones" { type = list(string) default = ["us-east-1a", "us-east-1b"] } -> Option C

4. Quick Check:

   List type with list default [OK]

Hint: Use type list(string) and default list [OK]

Common Mistakes:

• Omitting type for list variables
• Assigning list to string type
• Using string with commas instead of list