Query Data with Outputs

3min
|
Terraform
Video

In the previous tutorial, you used an input variable to parameterize your Terraform configuration. In this tutorial, you will use output values to present useful information to the Terraform user.

If you have not yet completed the Define Input Variables tutorial, do so before following this one.

Initial configuration

After following the previous tutorials, you will have a directory named learn-terraform-aws-instance with the following configuration.

# main.tf

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.16"
    }
  }

  required_version = ">= 1.2.0"
}

provider "aws" {
  region  = "us-west-2"
}

resource "aws_instance" "app_server" {
  ami           = "ami-08d70e59c07c61a3a"
  instance_type = "t2.micro"

  tags = {
    Name = var.instance_name
  }
}

# variables.tf

variable "instance_name" {
  description = "Value of the Name tag for the EC2 instance"
  type        = string
  default     = "ExampleAppServerInstance"
}

Ensure that your configuration matches this, and that you have initialized your configuration in the learn-terraform-aws-instance directory.

$ terraform init

Apply the configuration before continuing this tutorial. Respond to the confirmation prompt with a yes.

$ terraform apply

Output EC2 instance configuration

Create a file called outputs.tf in your learn-terraform-aws-instance directory.

Add the configuration below to outputs.tf to define outputs for your EC2 instance's ID and IP address.

output "instance_id" {
  description = "ID of the EC2 instance"
  value       = aws_instance.app_server.id
}

output "instance_public_ip" {
  description = "Public IP address of the EC2 instance"
  value       = aws_instance.app_server.public_ip
}

Inspect output values

You must apply this configuration before you can use these output values. Apply your configuration now. Respond to the confirmation prompt with yes.

$ terraform apply
aws_instance.app_server: Refreshing state... [id=i-0bf954919ed765de1]

Changes to Outputs:
  + instance_id        = "i-0bf954919ed765de1"
  + instance_public_ip = "54.186.202.254"

You can apply this plan to save these new output values to the Terraform state,
without changing any real infrastructure.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes


Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Outputs:

instance_id = "i-0bf954919ed765de1"
instance_public_ip = "54.186.202.254"

Terraform prints output values to the screen when you apply your configuration. Query the outputs with the terraform output command.

$ terraform output
instance_id = "i-0bf954919ed765de1"
instance_public_ip = "54.186.202.254"

You can use Terraform outputs to connect your Terraform projects with other parts of your infrastructure, or with other Terraform projects. To learn more, follow our in-depth tutorial, Output Data from Terraform.

Destroy infrastructure

Tip

If you plan to continue to later tutorials, skip this destroy step.

Destroy your infrastructure. Respond to the confirmation prompt with yes.

$ terraform destroy

Terraform used the selected providers to generate the following execution plan.
Resource actions are indicated with the following symbols:
  - destroy

Terraform will perform the following actions:

  # aws_instance.app_server will be destroyed
  - resource "aws_instance" "app_server" {
      - ami                          = "ami-08d70e59c07c61a3a" -> null
      - arn                          = "arn:aws:ec2:us-west-2:561656980159:instance/i-0bf954919ed765de1" -> null
##...

Plan: 0 to add, 0 to change, 1 to destroy.

Changes to Outputs:
  - instance_id        = "i-0bf954919ed765de1" -> null
  - instance_public_ip = "54.186.202.254" -> null

Do you really want to destroy all resources?
  Terraform will destroy all your managed infrastructure, as shown above.
  There is no undo. Only 'yes' will be accepted to confirm.

  Enter a value: yes

aws_instance.app_server: Destroying... [id=i-0bf954919ed765de1]
aws_instance.app_server: Still destroying... [id=i-0bf954919ed765de1, 10s elapsed]
aws_instance.app_server: Still destroying... [id=i-0bf954919ed765de1, 20s elapsed]
aws_instance.app_server: Still destroying... [id=i-0bf954919ed765de1, 30s elapsed]
aws_instance.app_server: Destruction complete after 31s

Destroy complete! Resources: 1 destroyed.