Read a change (~)

Reading an update

Edit one argument of a resource that already exists, and the plan shows only what changes:

  # demo_server.web will be updated in-place
  ~ resource "demo_server" "web" {
      ~ cpu = 1 -> 2
    }

Plan: 0 to add, 1 to change, 0 to destroy.

~ means update in place: the same server keeps running, with its id and IP, and one attribute changes. The line reads old value -> new value, and the attributes that don't change aren't listed at all.

There's a fourth symbol you'll meet later: -/+, replace. Some attributes can't be changed on a live resource (think of a disk's type, or a server's availability zone), so Terraform must destroy the resource and create a new one. The plan marks it must be replaced and counts it as both an add and a destroy. That's the one to look twice at: a new resource means a new id, and whatever was stored on the old one is gone.