Explicitly set update_policy on GCE instance group managers

pkg/model/gcemodel/autoscalinggroup.go

@@ -313,6 +313,7 @@ func (b *AutoscalingGroupModelBuilder) Build(c *fi.CloudupModelBuilderContext) e
 				Lifecycle:                   b.Lifecycle,
 				Zone:                        s(zone),
 				TargetSize:                  fi.PtrTo(int64(targetSize)),
+				UpdatePolicy:                &gcetasks.UpdatePolicy{MinimalAction: "REPLACE", Type: "OPPORTUNISTIC"},
 				BaseInstanceName:            s(ig.ObjectMeta.Name),
 				InstanceTemplate:            instanceTemplate,
 				ListManagedInstancesResults: "PAGINATED",

tests/integration/update_cluster/ha_gce/kubernetes.tf

@@ -497,6 +497,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-ha-gce-exa
   list_managed_instances_results = "PAGINATED"
   name                           = "a-master-us-test1-a-ha-gce-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-ha-gce-example-com.self_link
   }
@@ -508,6 +512,10 @@ resource "google_compute_instance_group_manager" "a-nodes-ha-gce-example-com" {
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-ha-gce-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-ha-gce-example-com.self_link
   }
@@ -519,6 +527,10 @@ resource "google_compute_instance_group_manager" "b-master-us-test1-b-ha-gce-exa
   list_managed_instances_results = "PAGINATED"
   name                           = "b-master-us-test1-b-ha-gce-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-b-ha-gce-example-com.self_link
   }
@@ -530,6 +542,10 @@ resource "google_compute_instance_group_manager" "b-nodes-ha-gce-example-com" {
   list_managed_instances_results = "PAGINATED"
   name                           = "b-nodes-ha-gce-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-ha-gce-example-com.self_link
   }
@@ -541,6 +557,10 @@ resource "google_compute_instance_group_manager" "c-master-us-test1-c-ha-gce-exa
   list_managed_instances_results = "PAGINATED"
   name                           = "c-master-us-test1-c-ha-gce-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-c-ha-gce-example-com.self_link
   }
@@ -552,6 +572,10 @@ resource "google_compute_instance_group_manager" "c-nodes-ha-gce-example-com" {
   list_managed_instances_results = "PAGINATED"
   name                           = "c-nodes-ha-gce-example-com"
   target_size                    = 0
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-ha-gce-example-com.self_link
   }

tests/integration/update_cluster/many-addons-gce/kubernetes.tf

@@ -425,6 +425,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-minimal-ex
   list_managed_instances_results = "PAGINATED"
   name                           = "a-master-us-test1-a-minimal-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-minimal-example-com.self_link
   }
@@ -436,6 +440,10 @@ resource "google_compute_instance_group_manager" "a-nodes-minimal-example-com" {
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-minimal-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-minimal-example-com.self_link
   }

tests/integration/update_cluster/minimal_gce/kubernetes.tf

@@ -401,6 +401,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-minimal-gc
   list_managed_instances_results = "PAGINATED"
   name                           = "a-master-us-test1-a-minimal-gce-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-minimal-gce-example-com.self_link
   }
@@ -412,6 +416,10 @@ resource "google_compute_instance_group_manager" "a-nodes-minimal-gce-example-co
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-minimal-gce-example-com"
   target_size                    = 2
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-minimal-gce-example-com.self_link
   }

tests/integration/update_cluster/minimal_gce_dns-none/kubernetes.tf

@@ -465,6 +465,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-minimal-gc
   list_managed_instances_results = "PAGINATED"
   name                           = "a-master-us-test1-a-minimal-gce-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-minimal-gce-example-com.self_link
   }
@@ -476,6 +480,10 @@ resource "google_compute_instance_group_manager" "a-nodes-minimal-gce-example-co
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-minimal-gce-example-com"
   target_size                    = 2
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-minimal-gce-example-com.self_link
   }

tests/integration/update_cluster/minimal_gce_ilb/kubernetes.tf

@@ -434,6 +434,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-minimal-gc
   list_managed_instances_results = "PAGINATED"
   name                           = "a-master-us-test1-a-minimal-gce-ilb-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-minimal-gce-ilb-example-com.self_link
   }
@@ -445,6 +449,10 @@ resource "google_compute_instance_group_manager" "a-nodes-minimal-gce-ilb-exampl
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-minimal-gce-ilb-example-com"
   target_size                    = 2
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-minimal-gce-ilb-example-com.self_link
   }

tests/integration/update_cluster/minimal_gce_ilb_longclustername/kubernetes.tf

@@ -434,6 +434,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-minimal-gc
   list_managed_instances_results = "PAGINATED"
   name                           = "a-master-us-test1-a-minimal-gce-with-a-very-very-very-ve-j0fh8f"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-minimal-gce-with-a-very-very-very-very-very-long-name-example-com.self_link
   }
@@ -445,6 +449,10 @@ resource "google_compute_instance_group_manager" "a-nodes-minimal-gce-with-a-ver
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-minimal-gce-with-a-very-very-very-very-very-long-qk78uj"
   target_size                    = 2
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-minimal-gce-with-a-very-very-very-very-very-long-name-example-com.self_link
   }

tests/integration/update_cluster/minimal_gce_longclustername/kubernetes.tf

@@ -401,6 +401,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-minimal-gc
   list_managed_instances_results = "PAGINATED"
   name                           = "a-master-us-test1-a-minimal-gce-with-a-very-very-very-ve-j0fh8f"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-minimal-gce-with-a-very-very-very-very-very-long-name-example-com.self_link
   }
@@ -412,6 +416,10 @@ resource "google_compute_instance_group_manager" "a-nodes-minimal-gce-with-a-ver
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-minimal-gce-with-a-very-very-very-very-very-long-qk78uj"
   target_size                    = 2
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-minimal-gce-with-a-very-very-very-very-very-long-name-example-com.self_link
   }

tests/integration/update_cluster/minimal_gce_plb/kubernetes.tf

@@ -458,6 +458,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-minimal-gc
   name                           = "a-master-us-test1-a-minimal-gce-plb-example-com"
   target_pools                   = [google_compute_target_pool.api-minimal-gce-plb-example-com.self_link]
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-minimal-gce-plb-example-com.self_link
   }
@@ -469,6 +473,10 @@ resource "google_compute_instance_group_manager" "a-nodes-minimal-gce-plb-exampl
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-minimal-gce-plb-example-com"
   target_size                    = 2
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-minimal-gce-plb-example-com.self_link
   }

tests/integration/update_cluster/minimal_gce_private/kubernetes.tf

@@ -401,6 +401,10 @@ resource "google_compute_instance_group_manager" "a-master-us-test1-a-minimal-gc
   list_managed_instances_results = "PAGINATED"
   name                           = "a-master-us-test1-a-minimal-gce-private-example-com"
   target_size                    = 1
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.master-us-test1-a-minimal-gce-private-example-com.self_link
   }
@@ -412,6 +416,10 @@ resource "google_compute_instance_group_manager" "a-nodes-minimal-gce-private-ex
   list_managed_instances_results = "PAGINATED"
   name                           = "a-nodes-minimal-gce-private-example-com"
   target_size                    = 2
+  update_policy {
+    minimal_action = "REPLACE"
+    type           = "OPPORTUNISTIC"
+  }
   version {
     instance_template = google_compute_instance_template.nodes-minimal-gce-private-example-com.self_link
   }

upup/pkg/fi/cloudup/gcetasks/instancegroupmanager.go

@@ -37,6 +37,7 @@ type InstanceGroupManager struct {
 	InstanceTemplate            *InstanceTemplate
 	ListManagedInstancesResults string
 	TargetSize                  *int64
+	UpdatePolicy                *UpdatePolicy
 
 	TargetPools []*TargetPool
 }
@@ -66,6 +67,10 @@ func (e *InstanceGroupManager) Find(c *fi.CloudupContext) (*InstanceGroupManager
 	actual.InstanceTemplate = &InstanceTemplate{ID: fi.PtrTo(lastComponent(r.InstanceTemplate))}
 	actual.ListManagedInstancesResults = r.ListManagedInstancesResults
 
+	if policy := r.UpdatePolicy; policy != nil {
+		actual.UpdatePolicy = &UpdatePolicy{MinimalAction: r.UpdatePolicy.MinimalAction, Type: r.UpdatePolicy.Type}
+	}
+
 	for _, targetPool := range r.TargetPools {
 		actual.TargetPools = append(actual.TargetPools, &TargetPool{
 			Name: fi.PtrTo(lastComponent(targetPool)),
@@ -104,6 +109,13 @@ func (_ *InstanceGroupManager) RenderGCE(t *gce.GCEAPITarget, a, e, changes *Ins
 		ListManagedInstancesResults: e.ListManagedInstancesResults,
 	}
 
+	if policy := e.UpdatePolicy; policy != nil {
+		i.UpdatePolicy = &compute.InstanceGroupManagerUpdatePolicy{
+			MinimalAction: e.UpdatePolicy.MinimalAction,
+			Type:          e.UpdatePolicy.Type,
+		}
+	}
+
 	for _, targetPool := range e.TargetPools {
 		i.TargetPools = append(i.TargetPools, targetPool.URL(t.Cloud))
 	}
@@ -181,9 +193,15 @@ type terraformInstanceGroupManager struct {
 	ListManagedInstancesResults string                     `cty:"list_managed_instances_results"`
 	Version                     *terraformVersion          `cty:"version"`
 	TargetSize                  *int64                     `cty:"target_size"`
+	UpdatePolicy                *terraformUpdatePolicy     `cty:"update_policy"`
 	TargetPools                 []*terraformWriter.Literal `cty:"target_pools"`
 }
 
+type terraformUpdatePolicy struct {
+	MinimalAction string `cty:"minimal_action"`
+	Type          string `cty:"type"`
+}
+
 type terraformVersion struct {
 	InstanceTemplate *terraformWriter.Literal `cty:"instance_template"`
 }
@@ -196,6 +214,12 @@ func (_ *InstanceGroupManager) RenderTerraform(t *terraform.TerraformTarget, a,
 		TargetSize:                  e.TargetSize,
 		ListManagedInstancesResults: e.ListManagedInstancesResults,
 	}
+	if policy := e.UpdatePolicy; policy != nil {
+		tf.UpdatePolicy = &terraformUpdatePolicy{
+			MinimalAction: e.UpdatePolicy.MinimalAction,
+			Type:          e.UpdatePolicy.Type,
+		}
+	}
 	tf.Version = &terraformVersion{
 		InstanceTemplate: e.InstanceTemplate.TerraformLink(),
 	}

upup/pkg/fi/cloudup/gcetasks/updatepolicy.go

@@ -0,0 +1,31 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+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.
+*/
+
+package gcetasks
+
+import "k8s.io/kops/upup/pkg/fi"
+
+// UpdatePolicy represents a GCE instance group manager UpdatePolicy
+type UpdatePolicy struct {
+	MinimalAction string
+	Type          string
+}
+
+var _ fi.CloudupHasDependencies = &UpdatePolicy{}
+
+func (_ *UpdatePolicy) GetDependencies(tasks map[string]fi.CloudupTask) []fi.CloudupTask {
+	return nil
+}