Environment variables (TF_VAR_) in Terraform - Mini Project: Build & Apply

Using Environment Variables (TF_VAR_) in Terraform

📖 Scenario: You are setting up a Terraform configuration to create a cloud resource. To keep your configuration flexible and secure, you want to use environment variables to pass values into Terraform variables.

🎯 Goal: Build a Terraform configuration that uses environment variables prefixed with TF_VAR_ to set variable values without hardcoding them in the configuration files.

📋 What You'll Learn

Create a Terraform variable named region with a default value

Set an environment variable named TF_VAR_region to override the default

Use the region variable in a Terraform resource configuration

Apply the configuration to verify the environment variable is used

💡 Why This Matters

🌍 Real World

Using environment variables to configure Terraform variables allows teams to keep sensitive or environment-specific data out of code files, making deployments safer and more flexible.

💼 Career

Cloud engineers and DevOps professionals often use environment variables to manage infrastructure configurations securely and efficiently across different environments.

1

Define a Terraform variable region

Create a Terraform variable named region with the default value us-west-1 inside a file called variables.tf. Write exactly this variable block:

Terraform

# Your code here

Need a hint?

This variable block defines a string variable named region with a default value.

2

Set the environment variable TF_VAR_region

Set an environment variable named TF_VAR_region with the value us-east-2 in your shell before running Terraform. Write this exact command for a Unix-like shell:

Terraform

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

# Your code here

Need a hint?

Use export TF_VAR_region="us-east-2" to set the environment variable in bash or similar shells.

3

Use the region variable in a Terraform provider block

In a file called main.tf, write a Terraform provider block for AWS that uses the variable region for its region attribute. Use this exact syntax:

Terraform

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

# Set environment variable in Unix shell
export TF_VAR_region="us-east-2"

# Your code here

Need a hint?

The provider block tells Terraform which AWS region to use, referencing the variable region.

4

Add a simple AWS S3 bucket resource using the region variable

In main.tf, add a resource block to create an AWS S3 bucket named my-tf-bucket with the bucket name my-tf-bucket-12345. Use the region variable indirectly by relying on the provider configuration. Write exactly this resource block:

Terraform

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

# Set environment variable in Unix shell
export TF_VAR_region="us-east-2"

provider "aws" {
  region = var.region
}

# Your code here

Need a hint?

This resource creates a private S3 bucket. The region is set by the provider using the variable.