feat(compute): add terraform sample for cross-zone repair functionality of RMIG (#905)

* feat(compute): add terraform sample for cross-zone repair functionality of rmig

* feat(compute): add terraform sample for cross-zone repair functionality of rmig

* relocate parent tag to surround all the terraform code

---------

Co-authored-by: Katie McLaughlin <[email protected]>
Co-authored-by: Katie McLaughlin <[email protected]>

Author: chayankumar999

compute/rmig_cross_zone_repair/main.tf

@@ -0,0 +1,81 @@
+/**
+ * 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.
+ */
+
+/**
+* Made to resemble:
+* gcloud beta compute instance-groups managed create czr-rmig \
+* --region us-central1 \
+* --size 3 \
+* --template example-template \
+* --target-distribution-shape balanced \
+* --instance-redistribution-type none \
+* --default-action-on-vm-failure=repair \
+* --on-repair-allow-changing-zone=YES \
+* --force-update-on-repair
+*/
+# [START compute_rmig_cross_zone_repair_parent_tag]
+terraform {
+  required_providers {
+    google = {
+      source  = "hashicorp/google-beta"
+      version = ">= 7.8.0"
+    }
+  }
+}
+
+resource "google_compute_instance_template" "default" {
+  name         = "example-template"
+  machine_type = "n2-standard-2"
+  disk {
+    source_image = "debian-cloud/debian-12"
+  }
+  network_interface {
+    network = "default"
+  }
+}
+
+# [START compute_rmig_cross_zone_repair]
+resource "google_compute_region_instance_group_manager" "default" {
+  provider           = google-beta
+  name               = "example-rmig"
+  base_instance_name = "example-rmig-instance"
+  region             = "us-central1"
+
+  target_size                      = 3
+  distribution_policy_target_shape = "BALANCED"
+
+  version {
+    instance_template = google_compute_instance_template.default.id
+  }
+
+  instance_lifecycle_policy {
+    default_action_on_failure = "REPAIR"
+    force_update_on_repair    = "YES"
+    on_repair {
+      allow_changing_zone = "YES"
+    }
+  }
+
+  update_policy {
+    instance_redistribution_type = "NONE"
+    type                         = "OPPORTUNISTIC"
+    minimal_action               = "REPLACE"
+    max_surge_fixed              = 0
+    max_unavailable_fixed        = 6
+  }
+}
+# [END compute_rmig_cross_zone_repair]
+# [END compute_rmig_cross_zone_repair_parent_tag]