Day 63 - Terraform Variables

• variables in Terraform are quite important, as you need to hold values of names of instance, configs , etc.

mkdir terraform-variables && cd terraform-variables

We can create a variables.tf file which will hold all the variables.

variable "filename" {
        default = "/home/ubuntu/terraform-variables/demo-var.txt"
}

variable "content" {
        default = "This is coming from a variable which was updated"
}

These variables can be accessed by var object in main.tf

Task-01

• Create a local file using Terraform Hint:

resource "local_file" "demo-var" {
    filename = var.filename
    content = var.content
}

• After completing all the steps mentioned in Day 61's blog, we can use a command to get our demo-var.txt file.

terraform init

terraform plan

terraform apply

ls && cat demo-var.txt

Data Types in Terraform

Map

• Terraform supports various data types like maps, lists, sets, and objects.

• Using Map Data Type

• For that create a folder for data-type and enter into it

• Create a file variables.tf in data-type folder and write below command

variable "filename" {
    default = "/home/ubuntu/terraform-variables/data-type/map-file.txt"
}

variable "map_file_contents" {
type = map
default = {
"content1" = "this is cool"
"content2" = "this is cool feature"
}
}

• Again create a main.tf file to get our map_file_contents

Copy

Copy

resource "local_file" "map-file1" {
        filename = var.filename
        content = var.map_file_contents["content1"]
}

resource "local_file" "map-file2" {
        filename = var.filename
        content = var.map_file_contents["content2"]
}

• After completing all the steps mentioned in Day 61's blog, we can use a command to get our map-file.txt file.

terraform init

terraform validate

terraform plan

terraform apply

ls && cat map-file.txt

terraform apply

ls && cat map-file.txt

Task-02

Demonstrate usage of List, Set and Object datatypes

• Use terraform to demonstrate usage of List, Set and Object datatypes in your data-type folder

# vim variable.tf
-------------------------------------------------------------------------------
# List

variable "regions" {
  type    = list(string)
  default = ["us-east-1", "us-east-2", "us-west-1"]
}


# Set

variable "environments" {
  type    = set(string)
  default = ["dev", "staging"]
}


# Object

variable "instances" {
  type = map(object({
    instance_type = string
    ami           = string
  }))
  default = {
    web = {
      instance_type = "t2.micro"
      ami           = "ami-0c7217cdde317cfec"
    }
    db = {
      instance_type = "t2.small"
      ami           = "ami-0c7217cdde317cfec"
    }
  }
}

• Create a file named main.tf with the following content:

# vim main.tf
-------------------------------------------------------------------------------
# List

output "regions_output" {
  value = var.regions
}

# Set

output "environments_output" {
  value = var.environments
}

# Object

output "instances_output" {
  value = var.instances
}

• After completing all the steps mentioned in Day 61's blog, we can use a command to get our demonstrate usage of List, Set and Object datatypes

terraform init

terraform validate

terraform plan

terraform apply

• Run the following Terraform command to refresh the state and capture outputs:

terraform refresh