Introduction

In the dynamic realm of infrastructure as code, the terraform import command stands as the bridge, allowing you to integrate existing resources into Terraform's declarative state. This guide explores the intricacies of terraform import, unraveling the processes it initiates to map existing resources to Terraform configurations. An example scenario will guide us through the importation journey, showcasing its impact on Terraform state.

1. Terraform import: Merging the Physical and Declarative Worlds

When managing existing resources that were not provisioned using Terraform, the terraform import command becomes the enabler for bringing these resources under Terraform's control. It allows you to link the physical infrastructure to the declarative Terraform state.

2. Example Scenario: Importing an Existing AWS EC2 Instance

Let's delve into an example scenario where you have an existing AWS EC2 instance, and you want to integrate it into your Terraform configuration. The goal is to utilize terraform import to map the EC2 instance to Terraform state.

2.1. Existing EC2 Instance:

Assume you have the following existing AWS EC2 instance named existing-instance with the instance ID i-0123456789abcdef0.

3. Importation Process: What Happens?

Executing terraform import initiates a process to link existing resources to Terraform state:

3.1. Resource Identification:

• Terraform identifies the existing resource to be imported, using the resource type and identifier.

3.2. State Initialization:

• If the resource does not exist in Terraform state, the command initializes the corresponding state entry.

3.3. Data Importation:

• The command fetches the existing resource's data from the provider (in this case, AWS) and imports it into Terraform state.

3.4. Output:

• The command provides feedback on the success or failure of the importation process, along with relevant details.

4. Applying the Command:

To initiate the importation process for the AWS EC2 instance, execute the following command:

terraform import aws_instance.example i-0123456789abcdef0

Here, aws_instance.example is the Terraform resource, and i-0123456789abcdef0 is the identifier for the existing EC2 instance.

5. Output of the Command:

Here's a hypothetical output of the terraform import command for our scenario:

Importing to terraform state: "aws_instance.example"
  arn:                "<computed>"
  associate_public_ip_address:  "true"
  availability_zone:       "us-east-1a"
  ... (other attributes)
aws_instance.example: Import complete!
  Imported aws_instance (ID: i-0123456789abcdef0)

6. Conclusion: Seamlessly Integrating Existing Resources

terraform import serves as the conduit for seamlessly integrating existing resources into Terraform state. By mapping the physical infrastructure to Terraform's declarative nature, it facilitates a unified and consistent approach to managing infrastructure.

May your Terraform configurations be harmoniously blended with existing resources, and may terraform import be your trusty guide in the integration journey! 🌐🔗