SOLVED - GCP HA-VPN between two projects - terraform doesn't find remote gateway

Terraform
1

I’m trying to build a HA-VPN between two projects in GCP, and while this appears it should be possible by providing the URL of the HA-VPN Gateway, when I do so, the terraform shows it’s actually looking for the remote gateway within my local project

resource "google_compute_vpn_tunnel" "tunnel1_prod1" {
  name                            = "gcp-vpn-gateway-1-tunnel-1"
  project                         = var.project
  region                          = var.region
  vpn_gateway              = google_compute_ha_vpn_gateway.ha_vpn_gateway1.id
  peer_gcp_gateway     = var.customer_gcp_peer_gateway
  shared_secret            = var.shared_secret
  router                          = google_compute_router.router1.id
  vpn_gateway_interface           = 0
}

The plan shows correctly that it has the url of the remote gateway as 'peer_gcp_gateway = “https://www.googleapis.com/compute/v1/projects/destination-project/regions/europe-west2/routers/manual-test-ha-vpn”
yet, when I then apply the change, it actually is looking in my project, for ‘manual-test-ha-vpn’ as indicated by the error message:

│ Error: Error creating VpnTunnel: googleapi: Error 404: The resource 'projects/origin-project/regions/europe-west2/vpnGateways/manual-test-ha-vpn' was not found, notFound
│ 
│   with module.gcp_vpn_ha_gateway["prod1"].google_compute_vpn_tunnel.tunnel1_prod1,
│   on modules/terraform-gcp-vpn-cust-gcp/main.tf line 34, in resource "google_compute_vpn_tunnel" "tunnel1_prod1":
│   34: resource "google_compute_vpn_tunnel" "tunnel1_prod1" {
│

You can see the URL either has been ignored, or changed to the point to the origin project, instead of the destination project when trying to find the gateway and I don’t understand why.

It maybe that I have the URL formatted incorrectly for the destination VPN Gateway, but I cannot find documentation to actually specify how this is meant to be formatted.

2

And as the magic of rubber ducking once again takes affect, I manually built the VPN, did a describe on it, and noticed the peer gateway there had infact /vpnGateways/ in the url instead of /routers/ - this change was what fixed it for me, and hopefully helps anyone else with this issue :smiley: