Add terraform sample for InstanceFlexibilityPolicy of RMIG

Author: chayankumar999

compute/rmig_instance_flexibility_policy/main.tf

@@ -0,0 +1,79 @@
+/**
+* Copyright 2024 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 alpha compute instance-groups managed create flex-igm --project=$PROJECT --region=us-central1 \
+* --target-distribution-shape=any-single-zone --instance-redistribution-type NONE \
+* --template example-template --size 3 \
+* --instance-selection "rank=1,name=best-choice,machine-type=n1-standard-1,n1-standard-2" \
+* --instance-selection "rank=2,name=still-ok,machine-type=n2-standard-1" \
+* --instance-selection "rank=3,name=if-nothing-else,machine-type=e2-standard-2"
+*/
+
+# [START compute_region_igm_instance_flexibility_policy_parent_tag]
+resource "google_compute_instance_template" "default" {
+  name         = "example-template"
+  machine_type = "e2-medium"
+  disk {
+    source_image = "debian-cloud/debian-11"
+  }
+  network_interface {
+    network = "default"
+  }
+}
+
+# [START compute_region_igm_instance_flexibility_policy]
+resource "google_compute_region_instance_group_manager" "default" {
+  name                      = "flex-igm"
+  base_instance_name        = "tf-test-flex-igm"
+  region                    = "us-central1"
+
+  target_size = 3
+  distribution_policy_target_shape = "ANY_SINGLE_ZONE"
+
+  version {
+    instance_template = google_compute_instance_template.default.id
+  }
+
+  instance_flexibility_policy {
+    instance_selections {
+      name = "best-choice"
+      rank = 1
+      machine_types = [ "n1-standard-1", "n1-standard-2" ]
+    }
+    instance_selections {
+      name = "still-ok"
+      rank = 2
+      machine_types = [ "n2-standard-1" ]
+    }
+    instance_selections {
+      name = "if-nothing-else"
+      rank = 3
+      machine_types = [ "e2-standard-2" ]
+    }
+  }
+
+  update_policy {
+    instance_redistribution_type = "NONE"
+    type                         = "OPPORTUNISTIC"
+    minimal_action               = "REPLACE"
+    max_surge_fixed              = 0
+    max_unavailable_fixed        = 6
+  }
+}
+# [END compute_region_igm_instance_flexibility_policy]
+# [END compute_region_igm_instance_flexibility_policy_parent_tag]