GCP compute_engine network interface terraform error - google-compute-engine

Question

My terraform file looks like this:
resource "google_compute_instance" "virtual_instance" {
name = "${var.instance_name}"
machine_type = "${var.instance_type}"
zone = "${var.zone}"
lifecycle {
ignore_changes = ["boot_disk.0.initialize_params.0.image"]
}
boot_disk {
initialize_params {
image = "ubuntu-os-cloud/ubuntu-1604-lts"
size = "30"
type = "pd-standard"
}
}
network_interface {
network = "default"
access_config {}
}
attached_disk {
source = "${google_compute_disk.managed_data_disk.name}"
mode = "READ_WRITE"
}
metadata {
}
}
This above code created the instance. But when i change then network_interface block as mentioned below
network_interface {
network = "${module.vpc.vpc_name}"
subnetwork = "${module.vpc.subnet_name}"
access_config {}
}
The VPC module is :
resource "google_compute_network" "vpc" {
name = "${var.name}-vpc"
auto_create_subnetworks = "false"
}
resource "google_compute_subnetwork" "subnet_public" {
name = "${var.subnet_name_public}"
ip_cidr_range = "${var.subnet_cidr_public}"
network = "${var.name}-vpc"
depends_on = ["google_compute_network.vpc"]
region = "${var.region}"
}
resource "google_compute_firewall" "firewall" {
name = "${var.name}-firewall"
network = "${google_compute_network.vpc.name}"
allow {
protocol = "icmp"
}
allow {
protocol = "tcp"
ports = ["22"]
}
source_ranges = ["0.0.0.0/0"]
}
when I changed into network_interface to custom values. It's throwing the error is
google_compute_instance.virtual_instance: Error creating network interfaces: exactly one of network or subnetwork must be provided
Please help me on this

Answer 1

Advance Thanks to #ydaetskcoR. If you choose custom values of network_interface. You can't mention both network and subnetwork. You will choose only subnetwork values mentioned below.
network_interface {
subnetwork = "${module.vpc.subnet_name}"
access_config {}
}