GCP Compute Engine using Terraform

Question

How to provision multiple instances in GCP Compute Engine using Terraform. I've tried using 'count' parameter in the resource block. But terraform is not provisioning more than one instance because the VM with a particular name is created once when first count is executed.

provider "google" {
version = "3.5.0"
credentials = file("battleground01-5c86f5873d44.json")
project = "battleground01"
region  = "us-east1"
zone    = "us-east1-b"
}

variable "node_count" {
default = "3"
}


resource "google_compute_instance" "appserver" {
count = "${var.node_count}"
name = "battleground"
machine_type = "f1-micro"


boot_disk {
initialize_params {
image = "debian-cloud/debian-9"
}
}

network_interface {
network = "default"
}

}

Answer 1

In order for this to work, you would have to make a slight change in the way you are naming your compute instances:

provider "google" {
  version     = "3.5.0"
  credentials = file("battleground01-5c86f5873d44.json")
  project     = "battleground01"
  region      = "us-east1"
  zone        = "us-east1-b"
}

variable "node_count" {
  type    = number
  default = 3
}


resource "google_compute_instance" "appserver" {
  count        = var.node_count
  name         = "battleground-${count.index}"
  machine_type = "f1-micro"


  boot_disk {
    initialize_params {
      image = "debian-cloud/debian-9"
    }
  }

  network_interface {
    network = "default"
  }

}

As you are using the count meta-argument, the way to access the array index is by using the count.index attribute [1]. You have also set the node_count variable default value to be a string and even though it would probably get converted to a number by Terraform, make sure to use the right variable types.

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[1] https://www.terraform.io/language/meta-arguments/count#the-count-object