feat: Add samples for custom node service account

Author: shannonxtreme

gke/autopilot/custom_service_account/main.tf

@@ -0,0 +1,51 @@
+/**
+* Copyright 2025 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.
+*/
+
+/**
+* Create an Autopilot cluster that uses a custom IAM node service account
+* with the minimum role for GKE.
+* Before you run this sample, create a custom service account by following
+* https://cloud.google.com/kubernetes-engine/docs/how-to/hardening-your-cluster#use_least_privilege_sa
+*/
+
+data "google_project" "project" {
+}
+
+resource "google_service_account" "default" {
+  account_id   = "gke-node-service-account"
+  display_name = "GKE node service account"
+}
+
+resource "google_project_iam_member" "default" {
+  project = data.google_project.project.project_id
+  role    = "roles/container.defaultNodeServiceAccount"
+  member  = "serviceAccount:${google_service_account.default.email}"
+}
+
+# [START gke_autopilot_custom_service_account]
+resource "google_container_cluster" "default" {
+  name     = "autopilot-custom-account"
+  location = "us-central1"
+
+  enable_autopilot = true
+
+  cluster_autoscaling {
+    auto_provisioning_defaults {
+      service_account = google_service_account.default.email
+    }
+  }
+}
+# [END gke_autopilot_custom_service_account]

gke/node_service_account/main.tf

@@ -0,0 +1,37 @@
+/**
+* Copyright 2025 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.
+*/
+
+# Create a custom IAM node service account with the minimum role for GKE
+
+# [START gke_node_service_account]
+# [START gke_node_service_account_create]
+resource "google_service_account" "default" {
+  account_id   = "gke-node-service-account"
+  display_name = "GKE node service account"
+}
+# [END gke_node_service_account_create]
+
+# [START gke_node_service_account_role]
+data "google_project" "project" {
+}
+
+resource "google_project_iam_member" "default" {
+  project = data.google_project.project.project_id
+  role    = "roles/container.defaultNodeServiceAccount"
+  member  = "serviceAccount:${google_service_account.default.email}"
+}
+# [END gke_node_service_account_role]
+# [END gke_node_service_account]

gke/standard/regional/node_pool/main.tf

@@ -14,18 +14,31 @@
 * limitations under the License.
 */
 
+# [START gke_standard_regional_node_pool_custom_sa]
 resource "google_service_account" "default" {
   account_id   = "service-account-id"
   display_name = "Service Account"
 }
 
+data "google_project" "project" {
+}
+
+resource "google_project_iam_member" "default" {
+  project = data.google_project.project.project_id
+  role    = "roles/container.defaultNodeServiceAccount"
+  member  = "serviceAccount:${google_service_account.default.email}"
+}
+# [END gke_standard_regional_node_pool_custom_sa]
+
+# [START gke_standard_regional_cluster]
 resource "google_container_cluster" "default" {
   name     = "gke-standard-regional-cluster"
   location = "us-central1"
 
   initial_node_count       = 1
   remove_default_node_pool = true
 }
+# [END gke_standard_regional_cluster]
 
 # [START gke_standard_regional_node_pool]
 resource "google_container_node_pool" "default" {