Terraform: update GKE cluster version, use locals and lookup to set…

… default values (googleforgames#1482)

* Terraform: update cluster version, use data source

Add Kubernetes version prefix parameter.
`google_container_engine_versions` allows to select proper node and master
version which applicable for every zone in the region.

* Add locals and lookup to handle missing keys

Avoid situation when missing one key could break deployment.

* Remove latest version to default version selection

Move data source to select versions of GKE into a separate review.

Co-authored-by: Mark Mandel <markmandel@google.com>

build/includes/terraform.mk

@@ -81,5 +81,9 @@ endif
 	GCP_CLUSTER_NAME=$(GCP_TF_CLUSTER_NAME) $(MAKE) gcloud-auth-cluster
 
 gcloud-terraform-destroy-cluster:
+ifndef GCP_PROJECT
+	$(eval GCP_PROJECT=$(shell sh -c "gcloud config get-value project 2> /dev/null"))
+endif
 	$(DOCKER_RUN) bash -c 'cd $(mount_path)/build/terraform/gke && \
-	 terraform destroy -target module.helm_agones.helm_release.agones -auto-approve && sleep 60 && terraform destroy -auto-approve'
+	terraform destroy -var project=$(GCP_PROJECT) -target module.helm_agones.helm_release.agones -auto-approve && sleep 60 && \
+	terraform destroy -var project=$(GCP_PROJECT) -auto-approve'

build/terraform/gke/module.tf

@@ -97,17 +97,21 @@ variable "feature_gates" {
   default = ""
 }
 
+variable "kubernetes_version" {
+  default = "1.15"
+}
 
 module "gke_cluster" {
   source = "../../../install/terraform/modules/gke"
 
   cluster = {
-    "name"             = var.name
-    "zone"             = var.zone
-    "machineType"      = var.machine_type
-    "initialNodeCount" = var.node_count
-    "project"          = var.project
-    "network"          = var.network
+    "name"              = var.name
+    "zone"              = var.zone
+    "machineType"       = var.machine_type
+    "initialNodeCount"  = var.node_count
+    "project"           = var.project
+    "network"           = var.network
+    "kubernetesVersion" = var.kubernetes_version
   }
 }
 

examples/terraform-submodules/gke/module.tf

@@ -46,7 +46,6 @@ variable "machine_type" {
 variable "node_count" {
   default = "4"
 }
-
 variable "zone" {
   default     = "us-west1-c"
   description = "The GCP zone to create the cluster in"

install/terraform/modules/gke/cluster.tf

@@ -19,37 +19,49 @@ terraform {
 
 data "google_client_config" "default" {}
 
+# A list of all parameters used in interpolation var.cluster
+# Set values to default if not key was not set in original map
+locals {
+  project           = lookup(var.cluster, "project", "agones")
+  zone              = lookup(var.cluster, "zone", "us-west1-c")
+  name              = lookup(var.cluster, "name", "test-cluster")
+  machineType       = lookup(var.cluster, "machineType", "n1-standard-4")
+  initialNodeCount  = lookup(var.cluster, "initialNodeCount", "4")
+  network           = lookup(var.cluster, "network", "default")
+  kubernetesVersion = lookup(var.cluster, "kubernetesVersion", "1.15")
+}
+
 # echo command used for debugging purpose
 # Run `terraform taint null_resource.test-setting-variables` before second execution
 resource "null_resource" "test-setting-variables" {
   provisioner "local-exec" {
     command = <<EOT
     ${format("echo Current variables set as following - name: %s, project: %s, machineType: %s, initialNodeCount: %s, network: %s, zone: %s",
-    var.cluster["name"], var.cluster["project"],
-    var.cluster["machineType"], var.cluster["initialNodeCount"], var.cluster["network"],
-    var.cluster["zone"])}
+    local.name, local.project,
+    local.machineType, local.initialNodeCount, local.network,
+local.zone)}
     EOT
-  }
+}
 }
 
 resource "google_container_cluster" "primary" {
-  name     = var.cluster["name"]
-  location = var.cluster["zone"]
-  project  = var.cluster["project"]
-  network  = var.cluster["network"]
+  name     = local.name
+  location = local.zone
+  project  = local.project
+  network  = local.network
 
-  min_master_version = "1.14"
+  min_master_version = local.kubernetesVersion
 
   node_pool {
     name       = "default"
-    node_count = var.cluster["initialNodeCount"]
+    node_count = local.initialNodeCount
 
     management {
       auto_upgrade = false
     }
 
     node_config {
-      machine_type = var.cluster["machineType"]
+      machine_type = local.machineType
 
       oauth_scopes = [
         "https://www.googleapis.com/auth/devstorage.read_only",
@@ -132,9 +144,9 @@ resource "google_container_cluster" "primary" {
 }
 
 resource "google_compute_firewall" "default" {
-  name    = "game-server-firewall-firewall-${var.cluster["name"]}"
-  project = var.cluster["project"]
-  network = var.cluster["network"]
+  name    = "game-server-firewall-firewall-${local.name}"
+  project = local.project
+  network = local.network
 
   allow {
     protocol = "udp"

install/terraform/modules/gke/variables.tf

@@ -25,11 +25,12 @@ variable "cluster" {
   type        = map
 
   default = {
-    "zone"             = "us-west1-c"
-    "name"             = "test-cluster"
-    "machineType"      = "n1-standard-4"
-    "initialNodeCount" = "4"
-    "project"          = "agones"
-    "network"          = "default"
+    "zone"              = "us-west1-c"
+    "name"              = "test-cluster"
+    "machineType"       = "n1-standard-4"
+    "initialNodeCount"  = "4"
+    "project"           = "agones"
+    "network"           = "default"
+    "kubernetesVersion" = "1.15"
   }
 }

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

@@ -139,7 +139,7 @@ You should have 6 nodes in `Ready` state.
 
 To delete all resources provisioned by Terraform:
 ```
-terraform destroy
+terraform destroy -var project="<YOUR_GCP_ProjectID>"
 ```
 
 ## Next Steps