Question

An engineer manages an AWS EC2 instance that runs a startup script needing an IAM policy to be fully attached before the instance boots. The instance configuration does not reference any attribute of the IAM policy resource, so Terraform sometimes creates them in parallel, causing the script to fail. Which change should the engineer make to guarantee correct ordering?

Accepted Answer

Add an explicit depends_on argument to the EC2 instance resource listing the IAM policy resource

Answer

Add a provisioner block to the IAM policy resource so it blocks until attachment completes

Answer

Run terraform apply twice so the IAM policy exists before the second apply creates the instance

Answer

Wrap both resources in a single module so Terraform processes them sequentially