terraform-google-compute-instance

Separated disk and static ip for better manageability
Substitutes $$REGION and $$ZONE in user-data

Usage:

Creates 3 instances and IP addresses with names test-1, test-2 and test-3. Machine type can be changed without destroying the boot disk.

data "google_compute_image" "coreos_stable" {
  family  = "coreos-stable"
  project = "coreos-cloud"
}

module "gci_test" {
  source = "github.com/matti/terraform-google-compute-instance"

  amount       = 3
  region       = "us-east1"
  name_prefix  = "test"
  machine_type = "custom-2-2048"
  disk_size    = "32"
  disk_image   = "${data.google_compute_image.coreos_stable.self_link}"
}