Allow a node pool to be created before it is destroyed

autogen/cluster.tf

@@ -219,14 +219,75 @@ resource "google_container_cluster" "primary" {
 /******************************************
   Create Container Cluster node pools
  *****************************************/
+{% if lifecycle_variant %}
+locals {
+  force_node_pool_recreation_resources = [
+    "disk_size_gb",
+    "disk_type",
+    "accelerator_count",
+    "accelerator_type",
+    "local_ssd_count",
+    "machine_type",
+    "preemptible",
+    "service_account",
+  ]
+}
+
+# This keepers list is based on the terraform google provider schemaNodeConfig
+# resources where "ForceNew" is "true"
+resource "random_id" "name" {
+  count       = length(var.node_pools)
+  byte_length = 2
+  prefix      = format("%s-", lookup(var.node_pools[count.index], "name"))
+  keepers = merge(
+    zipmap(
+      local.force_node_pool_recreation_resources,
+      [for keeper in local.force_node_pool_recreation_resources : lookup(var.node_pools[count.index], keeper, "")]
+    ),
+    {
+      labels = join(",",
+        keys(var.node_pools_labels["all"]),
+        keys(var.node_pools_labels[var.node_pools[count.index]["name"]]),
+        values(var.node_pools_labels["all"]),
+        values(var.node_pools_labels[var.node_pools[count.index]["name"]])
+      )
+    },
+    {
+      metadata = join(",",
+        keys(var.node_pools_metadata["all"]),
+        keys(var.node_pools_metadata[var.node_pools[count.index]["name"]]),
+        values(var.node_pools_metadata["all"]),
+        values(var.node_pools_metadata[var.node_pools[count.index]["name"]])
+      )
+    },
+    {
+      oauth_scopes = join(",",
+        var.node_pools_oauth_scopes["all"],
+        var.node_pools_oauth_scopes[var.node_pools[count.index]["name"]]
+      )
+    },
+    {
+      tags = join(",",
+        var.node_pools_tags["all"],
+        var.node_pools_tags[var.node_pools[count.index]["name"]]
+      )
+    }
+  )
+}
+
+{% endif %}
 resource "google_container_node_pool" "pools" {
   {% if beta_cluster %}
   provider = google-beta
   {% else %}
   provider = google
   {% endif %}
   count    = length(var.node_pools)
-  name     = var.node_pools[count.index]["name"]
+  {% if lifecycle_variant %}
+  name     = random_id.name.*.hex[count.index]
+  {% else %}
+  name     = lookup(var.node_pools[count.index], "name")
+  {% endif %}
   project  = var.project_id
   location = local.location
   cluster  = google_container_cluster.primary.name
@@ -342,6 +403,9 @@ resource "google_container_node_pool" "pools" {
 
   lifecycle {
     ignore_changes = [initial_node_count]
+    {% if lifecycle_variant %}
+    create_before_destroy = true
+    {% endif %}
   }
 
   timeouts {

cluster.tf

@@ -127,7 +127,7 @@ resource "google_container_cluster" "primary" {
 resource "google_container_node_pool" "pools" {
   provider = google
   count    = length(var.node_pools)
-  name     = var.node_pools[count.index]["name"]
+  name     = lookup(var.node_pools[count.index], "name")
   project  = var.project_id
   location = local.location
   cluster  = google_container_cluster.primary.name

helpers/generate_modules/generate_modules.py

@@ -54,6 +54,11 @@ def template_options(self, base):
         'private_cluster': True,
         'beta_cluster': True,
     }),
+    Module("./modules/private-cluster-lifecycle-variant", {
+        'module_path': '//modules/private-cluster-lifecycle-variant',
+        'private_cluster': True,
+        'lifecycle_variant': True,
+    }),
     Module("./modules/beta-public-cluster", {
         'module_path': '//modules/beta-public-cluster',
         'private_cluster': False,

modules/beta-private-cluster/cluster.tf

@@ -208,7 +208,7 @@ resource "google_container_cluster" "primary" {
 resource "google_container_node_pool" "pools" {
   provider = google-beta
   count    = length(var.node_pools)
-  name     = var.node_pools[count.index]["name"]
+  name     = lookup(var.node_pools[count.index], "name")
   project  = var.project_id
   location = local.location
   cluster  = google_container_cluster.primary.name

modules/beta-public-cluster/cluster.tf

@@ -203,7 +203,7 @@ resource "google_container_cluster" "primary" {
 resource "google_container_node_pool" "pools" {
   provider = google-beta
   count    = length(var.node_pools)
-  name     = var.node_pools[count.index]["name"]
+  name     = lookup(var.node_pools[count.index], "name")
   project  = var.project_id
   location = local.location
   cluster  = google_container_cluster.primary.name

modules/private-cluster-lifecycle-variant/auth.tf

@@ -0,0 +1,34 @@
+/**
+ * Copyright 2018 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// This file was automatically generated from a template in ./autogen
+
+/******************************************
+  Retrieve authentication token
+ *****************************************/
+data "google_client_config" "default" {
+  provider = google
+}
+
+/******************************************
+  Configure provider
+ *****************************************/
+provider "kubernetes" {
+  load_config_file       = false
+  host                   = "https://${local.cluster_endpoint}"
+  token                  = data.google_client_config.default.access_token
+  cluster_ca_certificate = base64decode(local.cluster_ca_certificate)
+}