Add existing Service account to terraform Google compute instance - google-cloud-platform

Question

Hello I am trying to add an existing service account to a new Google compute instance I am spinning up.
How can I attach the already existing account?
Here is what my file looks like
provider "google" {
project = var.project
region = "us-central1"
zone = "us-central1-c"
}
resource "google_compute_disk" "data_disk" {
name = "data-test"
size = 120
}
resource "google_compute_disk" "other_data_disk" {
name = "other-data-test"
size = 400
}
resource "google_compute_attached_disk" "data" {
disk = google_compute_disk.data_disk.id
instance = google_compute_instance.test_vm_instance.id
}
resource "google_compute_attached_disk" "other_data" {
disk = google_compute_disk.other_data_disk.id
instance = google_compute_instance.tyler_test_vm_instance.id
}
resource "google_compute_instance" "test_vm" {
name = "worker-test"
machine_type = "n2-standard-2"
min_cpu_platform = "Intel Ice Lake"
boot_disk {
initialize_params {
image = "ubuntu-2004-focal-v20210211"
}
}
network_interface {
network = var.gcp_project_network_name
subnetwork = var.subnet_name
#access_config {
#}
}
metadata_startup_script = "${file("./startup-script.sh")}"
What's the best way to insert add an already existing service account to the new VM.
I want to be able to create and destroy the VM without worrying about deleting this service account.

Answer 1

Add to this resource:
resource "google_compute_instance" "test_vm" {
...
service_account {
email = REPLACE_WITH_EXISTING_SERVICE_ACCOUNT_EMAIL_ADDRESS
scopes = ["cloud-platform"]
}
...
}