remote_subnet is required for dynamic tunnel

[orkenstein]

Even when set up to use dynamic, requires remote_subnet, otherwise returns:

$ terraform apply

Error: module.vpn-module-dynamic.google_compute_route.route: 1 error(s) occurred:

* module.vpn-module-dynamic.google_compute_route.route: __builtin_IntMath: divide by zero in:

${element(var.remote_subnet, (count.index%length(var.remote_subnet)))}

Configuration:

resource "google_compute_router" "vpn_cloud_router" {
  name    = "vpn-cloud-router"
  region  = "${var.region}"
  network = "${var.network}"
  project = "${var.project}"

  bgp {
    asn = "64515"
  }
}

module "vpn-module-dynamic" {
  source = "terraform-google-modules/vpn/google"

  project_id         = "${var.project}"
  network            = "${var.network}"
  region             = "${var.region}"
  gateway_name       = "vpn-gw-dynamic"
  tunnel_name_prefix = "vpn-tn-dynamic"

  shared_secret = "secrets"
  tunnel_count  = 1
  peer_ips      = ["1.1.1.1"]

  cr_name = "${google_compute_router.vpn_cloud_router.name}"

  bgp_cr_session_range     = ["169.254.0.1/30", "169.254.0.3/30"]
  bgp_remote_session_range = ["169.254.0.2", "169.254.0.4"]
  peer_asn                 = ["64516", "64517"]

  remote_subnet = ["10.200.10.0/24", "10.200.20.0/24"]
}

[morgante]

Is this just a documentation issue? @andreyk-code can you help?

[andreyk-code]

Have you tried using the string of the cloud router name in the "cr_name" arg instead of using the resource? Don't think the resource name is passable into the module.

cr_name = "vpn-cloud-router"

Please take a look at the /examples/multi-tunnel files for more reference.

[orkenstein]

cr_name = "vpn-cloud-router"
Yeah, this helps. Is it possible to pass the resource instead somehow?

[aaron-lane]

@andreyk-code Can you clarify why the name of a google_compute_router is not a valid value for cr_name? The offending count which is triggering this issue should be 0 unless cr_name is empty.