Variables and Outputs

Variables make your Terraform configuration flexible and reusable. Outputs expose values from your infrastructure for use by other configurations or scripts. This lesson covers input variables, output values, local values, and variable files.

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Input Variables

An input variable is declared with the variable block:

variable "region" {
  description = "The AWS region to deploy into"
  type        = string
  default     = "eu-west-2"
}

variable "instance_count" {
  description = "Number of instances to create"
  type        = number
  default     = 1
}

variable "enable_monitoring" {
  description = "Whether to enable detailed monitoring"
  type        = bool
  default     = false
}

Variable Arguments

Argument	Required	Purpose
description	No (recommended)	Documents the variable's purpose
type	No (recommended)	Constrains the variable type
default	No	Default value if none is provided
validation	No	Custom validation rules
sensitive	No	Hides the value in plan output
nullable	No	Whether the variable can be null

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Variable Types

Primitive Types