Environment variables (TF_VAR_) in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to reference the environment variable for the Terraform variable 'region'.

Terraform

variable "region" {
  type = string
  default = "us-west-1"
}

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

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

AAWS_REGION

Bregion

CTF_VAR_region

Denv_region

Attempts:

3 left

💡 Hint

Common Mistakes

Using the environment variable name directly in the code.

Confusing environment variable names with Terraform variable names.

The Terraform variable is accessed using var.region. The environment variable TF_VAR_region sets this variable but is not used directly in code.

2fill in blank

medium

Complete the command to set the environment variable for Terraform variable 'instance_type' in Linux shell.

Terraform

export [1]="t2.micro"

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Ainstance_type

Bterraform_instance_type

CAWS_INSTANCE_TYPE

DTF_VAR_instance_type

Attempts:

3 left

💡 Hint

Common Mistakes

Setting environment variable without the TF_VAR_ prefix.

Using unrelated environment variable names.

Terraform reads variables from environment variables prefixed with TF_VAR_. So to set instance_type, use TF_VAR_instance_type.

3fill in blank

hard

Fix the error in the Terraform variable declaration to use a default value from environment variable 'TF_VAR_bucket_name'.

Terraform

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

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A"my-default-bucket"

Bvar.TF_VAR_bucket_name

Cnull

Denv("TF_VAR_bucket_name")

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to call environment functions inside variable defaults.

Using variable names with TF_VAR_ prefix inside Terraform code.

Terraform does not support using environment variables directly inside variable defaults. The default must be a literal or expression. Environment variables set TF_VAR_bucket_name externally.

4fill in blank

hard

Fill both blanks to correctly use a variable 'ami_id' set via environment variable and reference it in resource.

Terraform

variable "ami_id" {
  type = string
}

resource "aws_instance" "example" {
  ami           = var.[1]
  instance_type = "t2.micro"
  tags = {
    Name = "ExampleInstance"
  }
  lifecycle {
    ignore_changes = ["[2]"]
  }
}

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Aami_id

Bami

Ctags

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names in references.

Not quoting attribute names in ignore_changes.

The variable is named ami_id and referenced as var.ami_id. The lifecycle block ignores changes to the ami_id attribute to prevent recreation.

5fill in blank

hard

Fill all three blanks to create a Terraform variable 'env' with default from environment variable, use it in provider, and output it.

Terraform

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

provider "aws" {
  region = var.[2]
}

output "environment" {
  value = var.[3]
}

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Adev

Benv

Dregion

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing variable names with environment variable names.

Using region instead of env in provider or output.

The variable env has a default value (e.g., "dev") which can be overridden by the environment variable TF_VAR_env. The provider uses var.env if it expects environment name, and the output shows var.env.