Add Terraform example for GKE custom VPC deployment (googleforgames#1697

)

* Add Custom VPC to terraform gke example
* Add subnetwork to configurable parameters

examples/terraform-submodules/gke/module.tf

@@ -14,7 +14,7 @@
 
 
 // Run:
-//  terraform apply -var project="<YOUR_GCP_ProjectID>" [-var agones_version="1.4.0"]
+//  terraform apply -var project="<YOUR_GCP_ProjectID>" [-var agones_version="1.8.0"]
 
 provider "google" {
   version = "~> 2.10"
@@ -56,6 +56,11 @@ variable "network" {
   description = "The name of the VPC network to attach the cluster and firewall rule to"
 }
 
+variable "subnetwork" {
+  default     = ""
+  description = "The subnetwork to host the cluster in. Required field if network value isn't 'default'."
+}
+
 variable "log_level" {
   default = "info"
 }
@@ -66,8 +71,8 @@ variable "feature_gates" {
 
 module "gke_cluster" {
   // ***************************************************************************************************
-  // Update ?ref= to the agones release you are installing. For example, ?ref=release-1.3.0 corresponds
-  // to Agones version 1.3.0
+  // Update ?ref= to the agones release you are installing. For example, ?ref=release-1.8.0 corresponds
+  // to Agones version 1.8.0
   // ***************************************************************************************************
   source = "git::https://github.com/googleforgames/agones.git//install/terraform/modules/gke/?ref=master"
 
@@ -78,13 +83,14 @@ module "gke_cluster" {
     "initialNodeCount" = var.node_count
     "project"          = var.project
     "network"          = var.network
+    "subnetwork"       = var.subnetwork
   }
 }
 
 module "helm_agones" {
   // ***************************************************************************************************
-  // Update ?ref= to the agones release you are installing. For example, ?ref=release-1.3.0 corresponds
-  // to Agones version 1.3.0
+  // Update ?ref= to the agones release you are installing. For example, ?ref=release-1.8.0 corresponds
+  // to Agones version 1.8.0
   // ***************************************************************************************************
   source = "git::https://github.com/googleforgames/agones.git//install/terraform/modules/helm3/?ref=master"
 

site/content/en/docs/Installation/Terraform/gke.md

@@ -88,6 +88,9 @@ Configurable parameters:
 - zone - the name of the [zone](https://cloud.google.com/compute/docs/regions-zones) you want your cluster to be
   created in (default is "us-west1-c")
 - network - the name of the VPC network you want your cluster and firewall rules to be connected to (default is "default")
+{{% feature publishVersion="1.9.0" %}}
+- subnetwork - the name of the subnetwork in which the cluster's instances are launched. (required when using non default network)
+{{% /feature %}}
 - log_level - possible values: Fatal, Error, Warn, Info, Debug (default is "info")
 - feature_gates - a list of alpha and beta version features to enable. For example, "PlayerTracking=true&ContainerPortAllocation=true"
 - gameserver_minPort - the lower bound of the port range which gameservers will listen on (default is "7000")
@@ -118,12 +121,30 @@ Next, make sure that you can authenticate using gcloud:
 ```
 gcloud auth application-default login
 ```
-
+{{% feature expiryVersion="1.9.0" %}}
 Now you can create your GKE cluster (optionally specifying the version of Agones you want to use):
 ```
-terraform apply -var project="<YOUR_GCP_ProjectID>" [-var agones_version="1.0.0"]
+terraform apply -var project="<YOUR_GCP_ProjectID>"
+```
+{{% /feature %}}
+
+{{% feature publishVersion="1.9.0" %}}
+#### Option 1: Creating the cluster in the default VPC
+To create your GKE cluster in the default VPC just specify the project variable.
+
+```
+terraform apply -var project="<YOUR_GCP_ProjectID>"
 ```
 
+#### Option 2: Creating the cluster in a custom VPC
+To create the cluster in a custom VPC you must specify the project, network and subnetwork variables.
+
+```
+terraform apply -var project="<YOUR_GCP_ProjectID>" -var network="<YOUR_NETWORK_NAME>" -var subnetwork="<YOUR_SUBNETWORK_NAME>"
+```
+{{% /feature %}}
+
+
 To verify that the cluster was created successfully, set up your kubectl credentials:
 ```
 gcloud container clusters get-credentials --zone us-west1-c agones-terraform-example