Terraform block - variables

Variables and Usage

variables.tf, default can be overwritten later

variable "region" {
  description = "AWS region to deploy resources"
  type        = string
  default     = "us-west-1"
}

It can be referenced by other blocks, via var.<variable_name>

provider "aws" {
  region = var.region
}

---

Override

Create a file named terraform.tfvar. Terraform automatically loads this file and overwrite the variable’s default values in variables.tf

region = "eu-west-1"

Use environment variable, with a format TF_VAR_XXX, terraform will search for the env as variable

export TF_VAR_region="ap-southeast-1"
terraform apply

Use -var flag on CLI

terraform apply -var="region=eu-west-2"

Order by Precedence

• Command Line Flags (higest)
• *.auto.tfvars files (for HTTP)
• *.tfvars files
• Env variable (TF_VAR_xxx)
• Variable block defaults

---

Output Variable

To check if your variable was picked up, use output block. Values will show up after terraform apply

output "chosen_region" {
  value = var.region
}

https://developer.hashicorp.com/terraform/language/values/variables