Module structure and conventions in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a Terraform module source path.

Terraform

module "example" {
  source = "[1]"
}

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

Aterraform-example

Bexample-module

C./modules/example

D/modules/example

Attempts:

3 left

💡 Hint

Common Mistakes

Using just the module name without a path.

Starting the path with a slash which makes it absolute instead of relative.

The source attribute in a Terraform module block specifies the relative path to the module folder. Using ./modules/example correctly points to a local module.

2fill in blank

medium

Complete the code to declare a variable inside a Terraform module.

Terraform

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

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

Aus-east-1

Bregion-1

Cdefault-region

Dus-west-2

Attempts:

3 left

💡 Hint

Common Mistakes

Using invalid or placeholder strings that are not real regions.

Leaving the default empty or missing.

The default value for a variable sets the default region. us-east-1 is a common AWS region example.

3fill in blank

hard

Fix the error in the module output declaration.

Terraform

output "instance_id" {
  value = [1]
}

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

Aexample.id

Baws_instance.example

Cinstance.id

Daws_instance.example.id

Attempts:

3 left

💡 Hint

Common Mistakes

Referencing the resource without the attribute.

Using incomplete or incorrect resource names.

The output value must reference the resource attribute correctly. aws_instance.example.id accesses the instance ID attribute.

4fill in blank

hard

Fill both blanks to create a module call with a variable and output.

Terraform

module "web_server" {
  source = "[1]"
  region = var.[2]
}

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

A./modules/webserver

Bregion

Cwebserver

D./webserver

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect source paths.

Passing variables without the var. prefix.

The source should point to the local module folder ./modules/webserver. The variable region is passed from var.region.

5fill in blank

hard

Fill all three blanks to define a module with variables and outputs correctly.

Terraform

module "db" {
  source = "[1]"
  db_name = var.[2]
  db_port = var.[3]
}

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

A./modules/database

Bname

Cport

D./database

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect source paths.

Mismatching variable names between module and call.

The module source is ./modules/database. Variables db_name and db_port are passed from var.name and var.port respectively.

Practice

1. What is the main purpose of using a Terraform module?

easy

A. To group and reuse cloud resource configurations

B. To write scripts for cloud providers

C. To store cloud provider credentials

D. To monitor cloud resource usage

Solution

1. Step 1: Understand module purpose

   Terraform modules are designed to group related cloud resources together for reuse and better organization.

2. Step 2: Compare options

   Only To group and reuse cloud resource configurations correctly describes this purpose. Other options describe unrelated tasks.

3. Final Answer:

   To group and reuse cloud resource configurations -> Option A

4. Quick Check:

   Module purpose = reuse and grouping [OK]

Hint: Modules group resources for reuse and clarity [OK]

Common Mistakes:

• Confusing modules with scripts
• Thinking modules store credentials
• Assuming modules monitor usage

2. Which of the following is the correct way to call a module named network located in a folder modules/network?

easy

A. module "network" { source = "modules/network" }

B. resource "network" { source = "modules/network" }

C. module network { path = "modules/network" }

D. resource "network" { path = "modules/network" }

Solution

1. Step 1: Identify module call syntax

   Terraform uses module "name" { source = "path" } to call modules.

2. Step 2: Check options

   Only module "network" { source = "modules/network" } uses correct module block and source attribute.

3. Final Answer:

   module "network" { source = "modules/network" } -> Option A

4. Quick Check:

   Module call uses module block and source [OK]

Hint: Use module block with source attribute for calling modules [OK]

Common Mistakes:

• Using resource instead of module
• Using path instead of source
• Omitting quotes around module name

3. Given this module folder structure:

modules/
  webserver/
    main.tf
    variables.tf
    outputs.tf

What is the purpose of the variables.tf file inside the module?

medium

A. To declare output values from the module

B. To define input variables for the module

C. To write the main resource definitions

D. To store provider configurations

Solution

1. Step 1: Understand file roles in module

   In Terraform modules, variables.tf defines input variables the module accepts.

2. Step 2: Match options

   To define input variables for the module correctly states this. Outputs are in outputs.tf, main resources in main.tf, and provider configs are outside modules.

3. Final Answer:

   To define input variables for the module -> Option B

4. Quick Check:

   variables.tf = input variables [OK]

Hint: variables.tf defines inputs; outputs.tf defines outputs [OK]

Common Mistakes:

• Confusing variables.tf with outputs.tf
• Putting resource code in variables.tf
• Adding provider config inside module

4. You wrote this module call:

module "db" {
  source = "modules/database"
  db_name = "prod"
}

But Terraform shows an error: "Unsupported argument: db_name". What is the likely cause?

medium

A. The source path is incorrect

B. Module names cannot contain underscores

C. The module does not declare an input variable named db_name

D. db_name should be declared inside main.tf

Solution

1. Step 1: Understand error meaning

   "Unsupported argument" means the module does not expect the given input variable.

2. Step 2: Check module inputs

   If db_name is not declared as a variable in the module's variables.tf, Terraform rejects it.

3. Final Answer:

   The module does not declare an input variable named db_name -> Option C

4. Quick Check:

   Input variables must be declared to be used [OK]

Hint: Declare input variables in module to avoid unsupported argument errors [OK]

Common Mistakes:

• Assuming source path causes unsupported argument
• Thinking module names restrict underscores
• Trying to declare inputs inside main.tf

5. You want to create a reusable module for deploying a virtual machine with optional tags. Which structure correctly supports optional tags with a default empty map?

hard

A. In variables.tf: variable "tags" { type = list(string) }

B. In main.tf: variable "tags" { default = null }

C. In outputs.tf: output "tags" { value = var.tags }

D. In variables.tf: variable "tags" { type = map(string) default = {} }

Solution

1. Step 1: Define optional input variable

   To make tags optional, define a variable with type map(string) and default empty map {}.

2. Step 2: Evaluate options

   In variables.tf: variable "tags" { type = map(string) default = {} } correctly defines this in variables.tf. In main.tf: variable "tags" { default = null } lacks type and uses null default. In outputs.tf: output "tags" { value = var.tags } is output, not input. In variables.tf: variable "tags" { type = list(string) } uses list instead of map.

3. Final Answer:

   In variables.tf: variable "tags" { type = map(string) default = {} } -> Option D

4. Quick Check:

   Optional map variable needs default empty map [OK]

Hint: Use map(string) with default {} for optional tags [OK]

Common Mistakes:

• Using list instead of map for tags
• Not setting a default value
• Declaring variables in outputs.tf