- In Terraform, outputs allow you to expose information about your deployed infrastructure.
- Outputs are useful for obtaining information about your infrastructure that you might need later.
- Output values can be used as input for other Terraform configurations or scripts.
- Outputs are also helpful for sharing information with your team or external processes.
- You can define multiple outputs in a single Terraform configuration to get different pieces of information.
- Outputs are handy when you need to know details about your infrastructure, like IP addresses, instance IDs, or DNS names.
- You can use an
outputblock to specify what information you want to extract.
Syntax:
output "local_name" {
value = resource_type.resource_name.attribute_or_argument
}Example:
terraform {
required_providers {
aws = {
source = "hashicorp/aws"
version = "~> 5.0"
}
}
}
provider "aws" {
region = var.aws_region
default_tags {
tags = {
Terraform = "yes"
Owner = var.owner
}
}
}resource "aws_instance" "myec2" {
ami = var.ec2_ami
instance_type = var.ec2_instance_type
user_data = <<EOF
#!/bin/bash
sudo yum update -y
sudo yum install httpd -y
sudo systemctl enable httpd
sudo systemctl start httpd
echo "<html><body><div><h1><center> Good day! This AWS Infrastructure is Deployed via Terraform ! </center></h1></div></body></html>" | sudo tee /var/www/html/index
EOF
tags = {
Name = "Linux2023"
}
}variable "aws_region" {
description = "AWS Region In Which Resources will be Created"
type = string
default = "us-east-1"
}
variable "owner" {
description = "Name of the Engineer who is creating Resources"
type = string
default = "Venkatesh"
}
variable "ec2_ami" {
description = "AWS EC2 AMI Amazon Linux 2023"
type = string
default = "ami-0df435f331839b2d6" # Amazon Linux 2023
}
variable "ec2_instance_type" {
description = "EC2 Instance Type"
type = string
default = "t2.micro"
}output "myec2_public_ip" {
description = "EC2 Instance Public IP"
value = aws_instance.myec2.public_ip
}
output "myec2_private_ip" {
description = "EC2 Instance Private IP"
value = aws_instance.myec2.private_ip
}
output "myec2_tags" {
description = "EC2 Instance Tags"
value = aws_instance.myec2.tags
}
output "myec2_public_dns" {
description = "Public DNS"
value = "http://${aws_instance.myec2.public_dns}"
}-
In the above example, We've defined four Outputs that will be displayed during
terraform planorterraform apply:
1.myec2_public_ip: EC2 Instance Public IP
2.myec2_private_ip: EC2 Instance Private IP
3.myec2_tags: EC2 Instance Tags
4.myec2_public_dns: Public DNS of EC2 Instance -
Lets Execute Terraform commands to understand resource behavior
terraform init: Initialize terraformterraform validate: Validate terraform codeterraform fmt: format terraform codeterraform plan: Review the terraform planterraform apply: Create Resources by terraform-
Example of
terraform plan -
Plan output shows the some outputs values to be known after apply
-
Example of
terraform apply -
terraform apply output shows the outputs values defined under
outputblocks -
You can notice
myec2_private_ipandmyec2_public_dns,myec2_public_ipandmyec2_tagsoutput being displayed afterterraform applyis run
-
terraform apply
$ terraform apply Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols: + create Terraform will perform the following actions: # aws_instance.myec2 will be created + resource "aws_instance" "myec2" { + ami = "ami-0df435f331839b2d6" + arn = (known after apply) + associate_public_ip_address = (known after apply) + availability_zone = (known after apply) + cpu_core_count = (known after apply) + cpu_threads_per_core = (known after apply) + disable_api_stop = (known after apply) + disable_api_termination = (known after apply) + ebs_optimized = (known after apply) + get_password_data = false + host_id = (known after apply) + host_resource_group_arn = (known after apply) + iam_instance_profile = (known after apply) + id = (known after apply) + instance_initiated_shutdown_behavior = (known after apply) + instance_lifecycle = (known after apply) + instance_state = (known after apply) + instance_type = "t2.micro" + ipv6_address_count = (known after apply) + ipv6_addresses = (known after apply) + key_name = (known after apply) + monitoring = (known after apply) + outpost_arn = (known after apply) + password_data = (known after apply) + placement_group = (known after apply) + placement_partition_number = (known after apply) + primary_network_interface_id = (known after apply) + private_dns = (known after apply) + private_ip = (known after apply) + public_dns = (known after apply) + public_ip = (known after apply) + secondary_private_ips = (known after apply) + security_groups = (known after apply) + source_dest_check = true + spot_instance_request_id = (known after apply) + subnet_id = (known after apply) + tags = { + "Name" = "Linux2023" } + tags_all = { + "Name" = "Linux2023" + "Owner" = "Venkatesh" + "Terraform" = "yes" } + tenancy = (known after apply) + user_data = "ac8b3be3af4efb32d5b9f2a6791b777944ae8ce6" + user_data_base64 = (known after apply) + user_data_replace_on_change = false + vpc_security_group_ids = (known after apply) } Plan: 1 to add, 0 to change, 0 to destroy. Changes to Outputs: + myec2_private_ip = (known after apply) + myec2_public_dns = (known after apply) + myec2_public_ip = (known after apply) + myec2_tags = { + Name = "Linux2023" + Owner = "Venkatesh" + Terraform = "yes" } 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 aws_instance.myec2: Creating... aws_instance.myec2: Still creating... [10s elapsed] aws_instance.myec2: Still creating... [20s elapsed] aws_instance.myec2: Still creating... [30s elapsed] aws_instance.myec2: Creation complete after 36s [id=i-0b859641747b6c60c] Apply complete! Resources: 1 added, 0 changed, 0 destroyed. Outputs: myec2_private_ip = "172.31.45.133" myec2_public_dns = "http://ec2-54-175-102-97.compute-1.amazonaws.com" myec2_public_ip = "54.175.102.97" myec2_tags = tomap({ "Name" = "Linux2023" "Owner" = "Venkatesh" "Terraform" = "yes" })
AWS Console
