LAB06-Data-Sources-EC2.md

LAB-06: Data Sources with Depends_on => Provision EC2

This scenario shows:

• how to use Data Source to fetch/retrieve data (existed resource information) from AWS

Code: https://github.com/omerbsezer/Fast-Terraform/blob/main/labs/data-sources/main.tf

Prerequisite

• You should have a look following lab:
  • LAB-00: Terraform Install, AWS Configuration with Terraform

Steps

• With data sources, existed resource information can be fetched/retrieved.
• "filter" provide to select/filter the existed instances
• "depends_on" provide to run the data block after resource created

...
data "aws_instance" "data_instance" {
    filter {
      name = "tag:Name"
      values = ["Basic Instance"]
    }

    depends_on = [
      aws_instance.instance
    ]
} 

output "instance_info" {
  value = data.aws_instance.data_instance
}
...

• Create main.tf:

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

  required_version = ">= 1.2.0"
}

provider "aws" {
	region = "eu-central-1"
}

resource "aws_instance" "instance" {
	ami           = "ami-0d1ddd83282187d18" # Ubuntu 22.04 eu-central-1 Frankfurt
	instance_type = "t2.nano"

	tags = {
		Name = "Basic Instance"
	}
}

# filter/select the existed instances
# depends_on if aws_instance.instance is created

data "aws_instance" "data_instance" {
    filter {
      name = "tag:Name"
      values = ["Basic Instance"]
    }

    depends_on = [
      aws_instance.instance
    ]
} 

output "instance_info" {
  value = data.aws_instance.data_instance
}

output "instance_public_ip" {
  value = data.aws_instance.data_instance.public_ip
}

Code: https://github.com/omerbsezer/Fast-Terraform/blob/main/labs/data-sources/main.tf

• Run init, validate command:

terraform init
terraform validate

• Run plan, apply command:

terraform plan
terraform apply

• With output, details can be viewed:

• Destroy infrastructure:

terraform destroy