Merge remote-tracking branch 'upstream/master' into OPS_31316_extend_for_ep

Author: czka

README.md

@@ -40,6 +40,7 @@ module "gke" {
       auto_repair     = true
       auto_upgrade    = true
       service_account = "project-service-account@<PROJECT ID>.iam.gserviceaccount.com"
+      preemptible     = false
     },
   ]
 
@@ -87,6 +88,8 @@ Then perform the following commands on the root folder:
 - `terraform plan` to see the infrastructure plan
 - `terraform apply` to apply the infrastructure build
 - `terraform destroy` to destroy the built infrastructure
+
+
 [^]: (autogen_docs_start)
 
 
@@ -151,6 +154,17 @@ Then perform the following commands on the root folder:
 [^]: (autogen_docs_end)
 
 ## Requirements
+
+Before this module can be used on a project, you must ensure that the following pre-requisites are fulfilled:
+
+1. Terraform and kubectl are [installed](#software-dependencies) on the machine where Terraform is executed.
+2. The Service Account you execute the module with has the right [permissions](#iam-roles).
+3. The Compute Engine and Kubernetes Engine APIs are [active](#enable-apis) on the project you will launch the cluster in.
+4. If you are using a Shared VPC, the APIs must also be activated on the Shared VPC host project and your service account needs the proper permissions there.
+
+The [project factory](https://github.com/terraform-google-modules/terraform-google-project-factory) can be used to provision projects with the correct APIs active and the necessary Shared VPC connections.
+
+### Software Dependencies
 ### Kubectl
 - [kubectl](https://github.com/kubernetes/kubernetes/releases) 1.9.x
 ### Terraform plugins
@@ -160,12 +174,12 @@ Then perform the following commands on the root folder:
 ### Configure a Service Account
 In order to execute this module you must have a Service Account with the following:
 
-#### Roles
+#### IAM Roles
 The service account with the following roles:
 - roles/compute.viewer on the project
 - roles/container.clusterAdmin on the project
 
-### Enable API's
+### Enable APIs
 In order to operate with the Service Account you must activate the following APIs on the project where the Service Account was created:
 
 - Compute Engine API - compute.googleapis.com

cluster_zonal.tf

@@ -24,7 +24,7 @@ resource "google_container_cluster" "zonal_primary" {
   project     = "${var.project_id}"
 
   zone             = "${var.zones[0]}"
-  additional_zones = "${slice(var.zones,1,length(var.zones))}"
+  additional_zones = ["${slice(var.zones,1,length(var.zones))}"]
 
   network            = "${data.google_compute_network.gke_network.self_link}"
   subnetwork         = "${data.google_compute_subnetwork.gke_subnetwork.self_link}"