Chapter 14 - Lifecycle Management

Ignoring changes and not updating the terraform when it doesn't need to be updated. https://developer.hashicorp.com/terraform/language/meta-arguments/lifecycle

• create_before_destroy - creates a new resource before destroying the old one.
• prevent_destroy - don't destroy these resources
• ignore_changes - ignores some of the changes of the resource
• replace_triggered by - (1.2+) - if something is changed somewhere else, then this resource will be replaced based on that trigger.

Preconditions and postconditions

---

resource "aws_instance" "example" {
  instance_type = "t2.micro"
  ami           = "ami-abc123"

  lifecycle {
    # The AMI ID must refer to an AMI that contains an operating system
    # for the `x86_64` architecture.
    precondition {
      condition     = data.aws_ami.example.architecture == "x86_64"
      error_message = "The selected AMI must be for the x86_64 architecture."
    }
  }
}