Terraform Tutorials: Variables Complete Reference

In Terraform, there are several types of variables that you can define, including:

1. String: A sequence of characters. Example: “hello”.
2. Number: A numeric value. Example: 42.
3. Boolean: A logical value that is either true or false.
4. List: A sequence of values of the same type. Example: [ “apples”, “oranges”, “bananas” ].
5. Map: A collection of key-value pairs, where the keys and values can be of any type. Example: { “name” = “John”, “age” = 30 }.
6. Object: A complex data type that can contain multiple attributes. Example: { name = “John”, age = 30, address = { street = “123 Main St”, city = “Anytown”, state = “CA” } }.
7. Tuple: A sequence of values of different types. Example: [ “John”, 30, true ].

Quick Tutorials on Terraform Variable

Terraform Variables and Configuration explained – 5 mins reading!

Terraform Variable Naming convention

Types of Terraform variable

• Types of Terraform variable – Number
• Types of Terraform variable – String
• Types of Terraform variable – List
• Types of Terraform variable – Map
• Types of Terraform variable – Boolean

Location of Declaring Terraform Variable

• Environment Variables
• Local Values
• Command Line
• terraform.tfvars
• anyotherfile.tfvars
• Terrform Outout Variable
• Example of terraform terraform.tfvars
• Terraform Environment Variables Exaplained!

One Example Code

variable "instance_count" {
  type = number
  default = 1
}

variable "instance_name" {
  type = string
  default = "Rajesh"
}

resource "aws_instance" "example-number" {
  count = var.instance_count
  ami           = "ami-053b0d53c279acc90"
  instance_type = "t2.micro"
  
  tags = {
    Name = var.instance_name
  }
}


variable "security_groups" {
  type = list(string)
  default = ["sg-0541801a7a059ba17"]
}


resource "aws_instance" "example-list" {
  ami           = "ami-053b0d53c279acc90"
  instance_type = "t2.micro"
  vpc_security_group_ids = var.security_groups
}

variable "instance_tags" {
  type = map(string)
  default = {
    Name = "my-instance4mMap-Rajesh"
  }
}

resource "aws_instance" "example-map" {
  ami           = "ami-053b0d53c279acc90"
  instance_type = "t2.micro"
  tags = var.instance_tags
}

variable "create_vm" {
  description = "If set to true, it will create vm"
   type   = bool
}

resource "aws_instance" "example-bool" {
  count   = var.create_vm ? 1 : 0
  ami           = "ami-053b0d53c279acc90"
  instance_type = "t2.micro"
  tags = var.instance_tags
}Code language: PHP (php)

Rajesh Kumar

I’m Rajesh Kumar, a DevOps, SRE, DevSecOps, Cloud, and Platform Engineering expert passionate about sharing practical knowledge, real-world experiences, and industry best practices. I have worked at Cotocus and regularly write about technology, travel, investing, health, product reviews, and digital marketing through my various platforms.

I publish technical articles at DevOps School, travel stories at Holiday Landmark, stock market insights at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at TrueReviewNow, and SEO and digital marketing strategies at Wizbrand.