Getting Started with Terraform - Second Edition

Using variable files

When running Terraform commands, you can optionally supply a variable file via the -var-file argument. The syntax of these files is the good old HCL, familiar to you from Terraform templates themselves. Create a new file named development.tfvars and set your variables there:

region = "eu-central-1" 
vpc_cidr = "172.0.0.0/16" 
subnet_cidrs = { 
  public = "172.0.16.0/24" 
  private = "172.0.17.0/24" 
} 

To use it, run terraform plan command with -var-file argument:

$> terraform plan -var-file=./development.tfvars 

It's much more reliable to use variable files for production stacks: you always know which values are there and you can store them in version control. And for sensitive things, such as a personal password to access ...