Using external resources from other state files in Terraform

Using External Resources in Terraform

This tutorial covers how to use external resources from other state files in Terraform.

Understanding Terraform State

Terraform state is used to map real-world resources to your configuration, keep track of metadata, and improve performance for large infrastructures.

Accessing External State Files

To access resources from an external state file, you can use the terraform_remote_state data source.

Example Usage:

    
data "terraform_remote_state" "vpc" {
  backend = "s3"
  config = {
    bucket = "my-terraform-state-bucket"
    key    = "vpc/terraform.tfstate"
    region = "us-west-1"
  }
}
    
  

Referencing External Resources

Once you have accessed the external state file, you can reference the resources within it as follows:

Example Reference:

    
resource "aws_security_group" "allow_tls" {
  vpc_id = data.terraform_remote_state.vpc.outputs.vpc_id

  # ... other configuration ...
}
    
  

Conclusion

By using the terraform_remote_state data source, you can easily integrate external resources into your Terraform configuration.