Variables

You can define changeable and reusable values in a terraform file by using the variable block. This block has three properties.

• description
• default
• type: this can be any, string etc.

variable "my_variable" {
    description = "A variable"
    default = "Corbusier"
    type = string
}

You can reference a variable using the var object followed by the variable name after a period.

resource "some_resource" "my_resource" {
    some_property = var.my_variable
}

You can assigned terraform variables in the command line using the -var flag.

terraform apply -var "<VARIABLE_NAME>=<VARIABLE_VALUE>"

You can assign terraform variables from a file by creating a terraform.tfvars file. Terraform will automatically read this file when running an apply. This file represents key-value pairs of defined variables.

# terraform.tfvars
my_variable = "Corbusier"

You can pass in other tfvars files by using the -var-file flag when using the terraform CLI.

terraform apply -var-file <FILE_NAME>.tfvars

You can assign objects as terraform variables using standard object syntax.

my_variable = {
    Name = "Corbusier"
    Age = 104
}