Terraform- Variables
Terraform supports different type of variables
- Strings
- Maps
- Lists
- Boolean
Strings
Example – single line
provider "aws"{
profile = "rprofile"
region = "ap-south-1"
}
variable "firststring" {
type = string
default = "this is my first string"
}
output "myfirstoutput" {
value = "${var.firststring}"
}
Example – multiline
provider "aws" {
profile = "rprofile"
region = "ap-south-1"
}
variable "multiline" {
type = string
default = <<EOT
1
2
EOT
}
output "outputvar"{
value = "${var.multiline}"
}
Numbers
Example
provider "aws"{
profile = rprofile
region = "ap-south-1"
}
variable "pie"{
type = number
default = 3.14
}
output "output1"{
value = "${var.pie}"
}
Bool
Example
provider "aws" {
profile="rprofile"
region="ap-south-1"
}
variable "IsiTTrue" {
type=bool
default=true
}
output "result" {
value= "${var.IsiTTrue}"
}
Null
The null value is represented by the unquoted symbol null.
Lists/Tuples
Lists/tuples are represented by a pair of square brackets containing a comma-separated sequence of values, like [“a”, 15, true].
List literals can be split into multiple lines for readability, but always require a comma between values.
Example 1
provider "aws" {
profile="rprofile"
region="ap-south-1"
}
variable "regions" {
type = list
default=["a","2","c"]
}
output "result" {
value="${var.regions}"
}
Example 2
provider "aws" {
profile="rprofile"
region="ap-south-1"
}
variable "regions" {
type = list
default=["a","2","c"]
}
output "result" {
value="${var.regions[0]}"
}
Map/Objects
Maps are a collection of string keys and string values.
Example
provider "aws" {
profile="rprofile"
region="ap-south-1"
}
variable "regions" {
type = map
default={
region1= "mumbai"
number1=1
}
}
output "result" {
value="${var.regions}"
}
Example2
provider "aws" {
profile="rprofile"
region="ap-south-1"
}
variable "regions" {
type = map
default={
region1= "mumbai"
number1=1
}
}
output "result" {
value="${var.regions["region1"]}"
}
Input Output variables
Example :- input the value from user and display it
provider "aws" {
profile="rprofile"
region="ap-south-1"
}
variable "myinput" {
type=string
}
output "result" {
value="${var.myinput}"
}
Example
variables (variable.tf)
variable "region" {
description = "Mumbai region"
type = string
default = "ap-south-1"
}
variable "keyname" {
type=string
default="devops"
}
variable "instance_type" {
type=string
default="t2.micro"
}
variable "name" {
type=string
default="Test"
}
main.tf
provider "aws"{
profile="rprofile"
region= var.region
}
resource "aws_instance" "myFirstInstance" {
ami = "ami-04bde106886a53080"
key_name = var.keyname
instance_type = var.instance_type
tags= {
Name = var.name
}
}
Example 2
variable.tf but without any default values
variable "instance_type" {
}create terraform.tfvars
instance_type=”t2.micro”
main.tf
resource "aws_instance" "myFirstInstance" {
ami = "ami-04bde106886a53080"
key_name = "devops"
instance_type = var.instance_type
tags= {
Name = "test"
}
}
Example 3 Terraform multiple tfvars file
variable.tf
variable "instance_type" {
}
variable "environment_name" {
}
stag.tfvars
instance_type="t2.micro"
environment_name ="stage"
main.tf
provider "aws"{
profile="rprofile"
region= "ap-south-1"
}
resource "aws_instance" "myFirstInstance" {
ami = "ami-04bde106886a53080"
key_name = "devops"
instance_type = var.instance_type
tags= {
Name = var.environment_name
}
}
