3 Ways to Reference Variables in Terraform

Variables can pass data into a Terraform configuration and can be used to parameterize the configuration.

They allow you to reuse the same configuration in different environments or for different purposes without hard-coding the values.

To run a Terraform configuration that references variables, your code will need to provide the values for those variables either by defining them in a TFVARS file or by passing them in as command-line arguments.

TFVARS

TFVARS is short for Terraform variables. Variables are a way to pass data into a Terraform configuration and can be used to parameterize the configuration. They can be defined in a file with a .tfvars extension or can be passed in as command-line arguments when running Terraform.

To use a TFVARS file, you will to pass the path to your TFVARS file as an argument to the terraform apply command:

terraform apply -var-file=path/to/vars.tfvars

Var Flag

Alternatively, you can use the -var flag to set the value of a single variable:

terraform apply -var 'region=us-east-2'

Set Variables in Configuration

You can also set variables in a Terraform configuration file using the variable block:

variable "region" {
default = "us-east-2"
}

It’s also possible to set variables using environment variables, but this is generally not recommended because it can make it challenging to understand the values being used in the configuration.