Add instance flexibility

This document describes how to add instance flexibility that lets you set multiple machine types in a MIG.

You can add instance flexibility when creating a MIG or by editing an existing MIG. To add the flexibility, configure an instance flexibility policy in the MIG. The policy overrides the machine type specified in the instance template. Each time the MIG creates a virtual machine (VM) instance, it automatically selects one of the machine types you've listed in the policy based on resource availability. You can also assign ranks to the lists of machine types to indicate your preference.

To know how instance flexibility works in a MIG, see About instance flexibility.

Before you begin

Make sure you choose machine types that are supported in the region where your MIG is located. To see the machine types in a region, see Available regions and zones.
If you haven't already, set up authentication. Authentication verifies your identity for access to Google Cloud services and APIs. To run code or samples from a local development environment, you can authenticate to Compute Engine by selecting one of the following options:
Select the tab for how you plan to use the samples on this page:
Console

When you use the Google Cloud console to access Google Cloud services and APIs, you don't need to set up authentication.
gcloud
1. Install the Google Cloud CLI. After installation, initialize the Google Cloud CLI by running the following command:
  gcloud init
  If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.
  
  Note: If you installed the gcloud CLI previously, make sure you have the latest version by running gcloud components update.
2. Set a default region and zone.
Terraform

To use the Terraform samples on this page in a local development environment, install and initialize the gcloud CLI, and then set up Application Default Credentials with your user credentials.
1. Install the Google Cloud CLI.
2. If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.
3. If you're using a local shell, then create local authentication credentials for your user account:
  gcloud auth application-default login
  You don't need to do this if you're using Cloud Shell.
  
  If an authentication error is returned, and you are using an external identity provider (IdP), confirm that you have signed in to the gcloud CLI with your federated identity.
For more information, see Set up authentication for a local development environment.
REST

To use the REST API samples on this page in a local development environment, you use the credentials you provide to the gcloud CLI.
For more information, see Authenticate for using REST in the Google Cloud authentication documentation.

Create a MIG with instance flexibility

Before creating a MIG, you must first create an instance template, if you don't already have one. You can then create a MIG with instance flexibility to override the machine type specified in the instance template.

Create a MIG with instance flexibility in one of the following ways:

Use multiple machine types
Use multiple machine types and preferences

Create a MIG with multiple machine types

Console

In the Google Cloud console, go to the Instance groups page.

Go to Instance groups

Click Create instance group.

In the Name field, enter a name for the MIG.

In the Instance template list, select the instance template that you want to use for the MIG.

Before you can specify the Number of instances and add Instance selections, you need to do the following:

Go to the Location section on the page and set a location as follows:
1. Select Multiple zones.
2. In the Regions and the Zones drop-downs, select a region and the zones in which you want to create the VMs in the MIG. If you selected a regional instance template, then the region of that template is selected by default.
3. In the Target distribution shape field, select Balanced, Any, or Any single zone.
  - If you select Balanced or Any single zone, then in the dialog that opens, click Disable instance redistribution.
  - If you select Any, then make sure that the Allow instance redistribution checkbox is not selected.
Go to the Autoscaling section on the page and delete the autoscaling configuration as follows:
1. In the Autoscaling mode drop-down, click Delete autoscaling configuration.
2. In the dialog that opens, click Delete.
Scroll back to the Number of instances field.

In the Number of instances field, specify the number of VMs that you want in the group.

In the Instance selections section, click Add selections.

The Instance selections window opens.

Click Add instance selection.
In the New instance selection section, do the following:
1. In the Name field, enter a name for the instance selection.
2. In the Machine types section, click Add machine type, select a machine type that you want to add in the instance selection, and then click Done.
  
  Repeat this step for each machine type that you want to add to the instance selection.
3. After you complete adding the machine types, click Done.

In the Instance selections window, click Done.

Leave the other fields in their default settings or modify as needed.

Click Create.

gcloud

To create a regional MIG with multiple machine types, use the instance-groups managed create command as follows:

gcloud compute instance-groups managed create INSTANCE_GROUP_NAME \
    --region REGION \
    --size TARGET_SIZE \
    --template INSTANCE_TEMPLATE_URL \
    --target-distribution-shape SHAPE \
    --instance-redistribution-type none \
    --instance-selection-machine-types MACHINE_TYPE,MACHINE_TYPE,...

Zonal MIGs don't support instance flexibility. However, if you want to create a MIG in a single zone, set the target distribution shape to any-single-zone. Furthermore, if you want a specific zone, use the any-single-zone distribution shape and include the --zones ZONE flag.

Replace the following:

INSTANCE_GROUP_NAME: the name of the MIG.
REGION: the region where you want to create the MIG.
TARGET_SIZE: the number of VMs you want the MIG to create and maintain.
INSTANCE_TEMPLATE_URL: the URL of the instance template that you want to use to create instances in the MIG. The URL can contain either the ID or name of the instance template. Specify one of the following values:
- For a regional instance template: projects/PROJECT_ID/regions/REGION/instanceTemplates/INSTANCE_TEMPLATE_ID
- For a global instance template: INSTANCE_TEMPLATE_ID
SHAPE: the target distribution shape. The value can be balanced, any, or any-single-zone.
MACHINE_TYPE: the machine types that you want to configure in the MIG—for example, n1-standard-16,n2-standard-16,e2-standard-16.

Terraform

If you haven't already created an instance template, which specifies the VM properties that you want for each VM in your MIG, create an instance template.

To create a regional MIG with multiple machine types, use the google_compute_region_instance_group_manager resource.

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          = "default-instance-selection"
      machine_types = ["n1-standard-16", "n2-standard-16", "e2-standard-16"]
    }
  }

  update_policy {
    instance_redistribution_type = "NONE"
    type                         = "OPPORTUNISTIC"
    minimal_action               = "REPLACE"
    max_surge_fixed              = 0
    max_unavailable_fixed        = 6
  }
}

To learn how to apply or remove a Terraform configuration, see Basic Terraform commands.

REST

To create a regional MIG with multiple machine types, make a POST request to the regionInstanceGroupManagers.insert method.

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/instanceGroupManagers

{
  "name": "INSTANCE_GROUP_NAME",
  "targetSize": TARGET_SIZE,
  "instanceTemplate": "INSTANCE_TEMPLATE_URL",
  "distributionPolicy": {
    "targetShape": "SHAPE"
  },
  "updatePolicy": {
    "instanceRedistributionType": "NONE"
  },
  "instanceFlexibilityPolicy": {
    "instanceSelections": {
      "INSTANCE_SELECTION": {
        "machineTypes": [
          "MACHINE_TYPE_1",
          "MACHINE_TYPE_2",
          ...
        ]
      }
    }
  }
}

Zonal MIGs don't support instance flexibility. However, if you want to create a MIG in a single zone, set the target distribution shape to ANY_SINGLE_ZONE. Furthermore, if you want a specific zone, use the ANY_SINGLE_ZONE distribution shape and include the distributionPolicy.zones[].zone field in the request.

Replace the following:

PROJECT_ID: your project ID.
REGION: the region where you want to create the MIG.
INSTANCE_GROUP_NAME: the name of the MIG.
TARGET_SIZE: the number of VMs you want the MIG to create and maintain.
INSTANCE_TEMPLATE_URL: the URL of the instance template that you want to use to create instances in the MIG. The URL can contain either the ID or name of the instance template. Specify one of the following values:
- For a regional instance template: projects/PROJECT_ID/regions/REGION/instanceTemplates/INSTANCE_TEMPLATE_ID
- For a global instance template: INSTANCE_TEMPLATE_ID
SHAPE: the target distribution shape. The value can be BALANCED, ANY, or ANY_SINGLE_ZONE.
INSTANCE_SELECTION: the name for the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG—for example, "n1-standard-16","n2-standard-16","e2-standard-16".

Create a MIG with multiple machine types and preferences

Console

In the Google Cloud console, go to the Instance groups page.

Go to Instance groups
Click Create instance group.
In the Name field, enter a name for the MIG.
In the Instance template list, select the instance template that you want to use for the MIG.
Before you can specify the Number of instances and add Instance selections, you need to do the following:
1. Go to the Location section on the page and set a location as follows:
  1. Select Multiple zones.
  2. In the Regions and the Zones drop-downs, select a region and the zones in which you want to create the VMs in the MIG. If you selected a regional instance template, then the region of that template is selected by default.
  3. In the Target distribution shape field, select Balanced, Any, or Any single zone.
    - If you select Balanced or Any single zone, then in the dialog that opens, click Disable instance redistribution.
    - If you select Any, then make sure that the Allow instance redistribution checkbox is not selected.
2. Go to the Autoscaling section on the page and delete the autoscaling configuration as follows:
  1. In the Autoscaling mode drop-down, click Delete autoscaling configuration.
  2. In the dialog that opens, click Delete.
3. Scroll back to the Number of instances field.
In the Number of instances field, specify the number of VMs that you want in the group.
In the Instance selections section, click Add selections.

The Instance selections window opens. Repeat the following steps for each instance selection that you want to add in the MIG.
1. Click Add instance selection.
2. In the New instance selection section, do the following:
  1. In the Name field, enter a name for the instance selection.
  2. In the Rank field, enter the order of preference among the instance selections that you add for the MIG.
  3. In the Machine types section, click Add machine type, select a machine type that you want to add in the instance selection, and then click Done.
    
    Repeat this step for each machine type that you want to add to the instance selection.
  4. After you complete adding the machine types, click Done.
After you complete adding the instance selections, click Done.
Leave the other fields in their default settings or modify as needed.
Click Create.

gcloud

To create a regional MIG with multiple machine types and preferences, use the instance-groups managed create command.

gcloud compute instance-groups managed create INSTANCE_GROUP_NAME \
    --region REGION \
    --size TARGET_SIZE \
    --template INSTANCE_TEMPLATE_URL \
    --target-distribution-shape SHAPE \
    --instance-redistribution-type none \
    --instance-selection "name=INSTANCE_SELECTION_1,machine-type=MACHINE_TYPE_1,machine-type=MACHINE_TYPE_2,rank=RANK_1" \
    --instance-selection "name=INSTANCE_SELECTION_2,machine-type=MACHINE_TYPE_3,machine-type=MACHINE_TYPE_4,rank=RANK_2"

Replace the following:

INSTANCE_GROUP_NAME: the name of the MIG.
REGION: the region where you want to create the MIG.
TARGET_SIZE: the number of VMs that you want the MIG to create and maintain.
INSTANCE_TEMPLATE_URL: the URL of the instance template that you want to use to create instances in the MIG. The URL can contain either the ID or name of the instance template. Specify one of the following values:
- For a regional instance template: projects/PROJECT_ID/regions/REGION/instanceTemplates/INSTANCE_TEMPLATE_ID
- For a global instance template: INSTANCE_TEMPLATE_ID
SHAPE: the target distribution shape. The value can be balanced, any, or any-single-zone. The other target distribution shapes are not supported.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

Terraform

If you haven't already created an instance template, which specifies the VM properties that you want for each VM in your MIG, create an instance template.

To create a regional MIG with multiple machine types and preferences, use the google_compute_region_instance_group_manager resource.

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
  }
}

To learn how to apply or remove a Terraform configuration, see Basic Terraform commands.

REST

To create a regional MIG with multiple machine types and preferences, make a POST request to the regionInstanceGroupManagers.insert method.

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/instanceGroupManagers

{
  "name": "INSTANCE_GROUP_NAME",
  "targetSize": TARGET_SIZE,
  "instanceTemplate": "INSTANCE_TEMPLATE_URL",
  "distributionPolicy": {
    "targetShape": "SHAPE"
  },
  "updatePolicy": {
    "instanceRedistributionType": "NONE"
  },
  "instanceFlexibilityPolicy": {
    "instanceSelections": {
      "INSTANCE_SELECTION_1": {
        "machineTypes": [
          "MACHINE_TYPE_1",
          "MACHINE_TYPE_2",
          ...
        ],
        "rank": RANK_1
      },
      "INSTANCE_SELECTION_2": {
        "machineTypes": [
          "MACHINE_TYPE_3",
          "MACHINE_TYPE_4",
          ...
        ],
        "rank": RANK_2
      },
      ...
    }
  }
}

Replace the following:

PROJECT_ID: your project ID.
REGION: the region where you want to create the MIG.
INSTANCE_GROUP_NAME: the name of the MIG.
TARGET_SIZE: the number of VMs that you want the MIG to create and maintain.
INSTANCE_TEMPLATE_URL: the URL of the instance template that you want to use to create instances in the MIG. The URL can contain either the ID or name of the instance template. Specify one of the following values:
- For a regional instance template: projects/PROJECT_ID/regions/REGION/instanceTemplates/INSTANCE_TEMPLATE_ID
- For a global instance template: INSTANCE_TEMPLATE_ID
SHAPE: the target distribution shape. The value can be BALANCED, ANY, or ANY_SINGLE_ZONE. The other target distribution shapes are not supported.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

Create a MIG with multiple machine types, preferences, and additional overrides

When creating a MIG with multiple machine types, optionally, you can set a minimum CPU platform and disk definitions for each instance selection.

Console

In the Google Cloud console, go to the Instance groups page.

Go to Instance groups
Click Create instance group.
In the Name field, enter a name for the MIG.
In the Instance template list, select the instance template that you want to use for the MIG.
Before you can specify the Number of instances and add Instance selections, you need to do the following:
1. Go to the Location section on the page and set a location as follows:
  1. Select Multiple zones.
  2. In the Regions and the Zones drop-downs, select a region and the zones in which you want to create the VMs in the MIG. If you selected a regional instance template, then the region of that template is selected by default.
  3. In the Target distribution shape field, select Balanced, Any, or Any single zone.
    - If you select Balanced or Any single zone, then in the dialog that opens, click Disable instance redistribution.
    - If you select Any, then make sure that the Allow instance redistribution checkbox is not selected.
2. Go to the Autoscaling section on the page and delete the autoscaling configuration as follows:
  1. In the Autoscaling mode drop-down, click Delete autoscaling configuration.
  2. In the dialog that opens, click Delete.
3. Scroll back to the Number of instances field.
In the Number of instances field, specify the number of VMs that you want in the group.
In the Instance selections section, click Add selections.

The Instance selections window opens. Repeat the following steps for each instance selection that you want to add in the MIG.
1. Click Add instance selection.
2. In the New instance selection section, do the following:
  1. In the Name field, enter a name for the instance selection.
  2. In the Rank field, enter the order of preference among the instance selections that you add for the MIG.
  3. In the Machine types section, click Add machine type, select a machine type that you want to add in the instance selection, and then click Done.
    
    Repeat this step for each machine type that you want to add to the instance selection.
  4. If you want to override the minimum CPU platform specified in the instance template, then select the Override CPU platform for this selection checkbox. In the CPU platform list, select the platform that you want to use for the instance selection.
  5. If you want to override the disk configuration specified in the instance template or to attach a storage, then select the Override disks checkbox.
    - To override the boot disk, in the Boot disk section, click Change, and follow the prompts.
    - To attach a storage, click Add new disk or Attach existing disk, and follow the prompts.
  6. After you complete adding the machine types and the overrides, click Done.
After you complete adding the instance selections, click Done.
Leave the other fields in their default settings or modify as needed.
Click Create.

gcloud

Use the instance-groups managed create command.

gcloud compute instance-groups managed create INSTANCE_GROUP_NAME \
    --region REGION \
    --size TARGET_SIZE \
    --template INSTANCE_TEMPLATE_URL \
    --force-update-on-repair \
    --target-distribution-shape SHAPE \
    --instance-redistribution-type none \
    --instance-flexibility-policy={"instanceSelections": \
        {"INSTANCE_SELECTION_1":{"rank":RANK_1,"machineTypes":["MACHINE_TYPE_1","MACHINE_TYPE_2"],"minCpuPlatform":"MIN_CPU_PLATFORM_1","disks":[{"deviceName":"DEVICE_NAME_1","boot":true,"initializeParams":{"sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE_NAME"}}]}, \
        "INSTANCE_SELECTION_2":{"rank":RANK_2,"machineTypes":["MACHINE_TYPE_3","MACHINE_TYPE_4"],"minCpuPlatform":"MIN_CPU_PLATFORM_2","disks":[{"deviceName":"DEVICE_NAME_2","boot":true,"initializeParams":{"sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE_NAME"}}]}}}

You can also use a YAML or JSON file to configure the instance flexibility policy. To do so, use the --flags-file flag instead of the --instance-flexibility-policy flag and specify the filename. For example, use --flags-file=FILE_NAME.YAML.

Replace the following:

INSTANCE_GROUP_NAME: the name of the MIG.
REGION: the region where you want to create the MIG.
TARGET_SIZE: the number of VMs that you want the MIG to create and maintain.
INSTANCE_TEMPLATE_URL: the URL of the instance template that you want to use to create instances in the MIG. The URL can contain either the ID or name of the instance template. Specify one of the following values:
- For a regional instance template: projects/PROJECT_ID/regions/REGION/instanceTemplates/INSTANCE_TEMPLATE_ID
- For a global instance template: INSTANCE_TEMPLATE_ID
SHAPE: the target distribution shape. The value can be balanced, any, or any-single-zone. The other target distribution shapes are not supported.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
MIN_CPU_PLATFORM: the minimum CPU platform for the instances.
DEVICE_NAME: the device name for the disk.
IMAGE_PROJECT: the project ID of the source image.
IMAGE_NAME: the name of the source image.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

Terraform

If you haven't already created an instance template, which specifies the VM properties that you want for each VM in your MIG, create an instance template.

To create a regional MIG with multiple machine types, preferences, and additional overrides, use the google_compute_region_instance_group_manager resource.

resource "google_compute_region_instance_group_manager" "default" {
  provider           = google-beta
  name               = "flex-igm"
  base_instance_name = "flex-igm-instance"
  region             = "us-central1"

  target_size                      = 2
  distribution_policy_target_shape = "ANY"

  version {
    instance_template = google_compute_instance_template.default.id
  }

  instance_flexibility_policy {
    instance_selections {
      name          = "first-preference"
      rank          = 1
      machine_types = ["n4-standard-4"]
      disks {
        auto_delete  = true
        device_name  = "boot"
        boot         = true
        source_image = "projects/debian-cloud/global/images/family/debian-12"
        disk_size_gb = 10
        disk_type    = "hyperdisk-balanced"
      }
    }

    instance_selections {
      name             = "second-preference"
      rank             = 2
      machine_types    = ["n2-standard-4"]
      min_cpu_platform = "Intel Ice Lake"
      disks {
        auto_delete  = true
        device_name  = "boot"
        boot         = true
        source_image = "projects/debian-cloud/global/images/family/debian-12"
        disk_size_gb = 10
        disk_type    = "pd-ssd"
      }
    }
  }

  instance_lifecycle_policy {
    force_update_on_repair = "YES"
  }

  update_policy {
    instance_redistribution_type = &quot;NONE"
    type                         = "OPPORTUNISTIC"
    minimal_action               = "REPLACE"
    max_surge_fixed              = 0
    max_unavailable_fixed        = 6
  }
}

To learn how to apply or remove a Terraform configuration, see Basic Terraform commands.

REST

Make a POST request to the beta regionInstanceGroupManagers.insert method.

POST https://compute.googleapis.com/compute/beta/projects/PROJECT_ID/regions/REGION/instanceGroupManagers

{
"name": "INSTANCE_GROUP_NAME",
"targetSize": "TARGET_SIZE",
"instanceTemplate": "INSTANCE_TEMPLATE_URL",
"distributionPolicy": {
  "targetShape": "SHAPE"
},
"updatePolicy": {
  "instanceRedistributionType": "NONE"
},
"instanceLifecyclePolicy": {
  "forceUpdateOnRepair": "YES",
},
"instanceFlexibilityPolicy": {
  "instanceSelections": {
    "INSTANCE_SELECTION_1": {
      "machineTypes": ["MACHINE_TYPE_1", "MACHINE_TYPE_2", …],
      "minCpuPlatform": "MIN_CPU_PLATFORM_1",
      "disks": [
        {
          "deviceName": "DEVICE_NAME_1",
          "initializeParams": {
            "sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE_NAME"
          },
          "boot": true
        }
      ],
      "rank": RANK_1
    },
    "INSTANCE_SELECTION_2": {
      "machineTypes": ["MACHINE_TYPE_3", "MACHINE_TYPE_4", …],
      "minCpuPlatform": "MIN_CPU_PLATFORM_2",
      "disks": [
        {
          "deviceName": "DEVICE_NAME_2",
          "initializeParams": {
            "sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE_NAME"
          },
          "boot": true
        }
      ],
      "rank": RANK_2
    }
  }
}
}

Replace the following:

PROJECT_ID: your project ID.
REGION: the region where you want to create the MIG.
INSTANCE_GROUP_NAME: the name of the MIG.
TARGET_SIZE: the number of VMs that you want the MIG to create and maintain.
INSTANCE_TEMPLATE_URL: the URL of the instance template that you want to use to create instances in the MIG. The URL can contain either the ID or name of the instance template. Specify one of the following values:
- For a regional instance template: projects/PROJECT_ID/regions/REGION/instanceTemplates/INSTANCE_TEMPLATE_ID
- For a global instance template: INSTANCE_TEMPLATE_ID
SHAPE: the target distribution shape. The value can be BALANCED, ANY, or ANY_SINGLE_ZONE. The other target distribution shapes are not supported.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
MIN_CPU_PLATFORM: the minimum CPU platform for the instances.
DEVICE_NAME: the device name for the disk.
IMAGE_PROJECT: the project ID of the source image.
IMAGE_NAME: the name of the source image.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

Add instance flexibility to an existing MIG

You can add instance flexibility to an existing MIG. You can set multiple machine types and also set preferences for certain machine types.

If your MIG already has VMs in it, those VMs continue to use the machine type specified in the instance template. If you want the existing VMs in the MIG to use the machine types from the instance flexibility policy, then, after you add the policy, delete the existing VMs and then resize the MIG to the required number of VMs. When resizing, the new VMs will use the machine types from the policy.

To modify an existing instance flexibility policy, see Change instance flexibility configuration.

Add instance flexibility to a MIG in one of the following ways:

Add multiple machine types
Add multiple machine types and preferences
Add multiple machine types, preferences, and additional overrides

Add multiple machine types

Console

In the Google Cloud console, go to the Instance groups page.

Go to Instance groups

Click the name of the MIG in which you want to set multiple machine types.

Click Edit.

Click Instance flexibility to expand the section.

In the Instance selections section, click Add selections.

The Instance selections window opens.

Click Add instance selection.
In the New instance selection section, do the following:
1. In the Name field, enter a name for the instance selection.
2. In the Machine types section, click Add machine type, select a machine type that you want to add in the instance selection, and then click Done.
  
  Repeat this step for each machine type that you want to add to the instance selection.
3. After you complete adding the machine types, click Done.

In the Instance selections window, click Done.

Click Save.

gcloud

To add multiple machine types to an existing MIG, use the instance-groups managed update command.

gcloud compute instance-groups managed update INSTANCE_GROUP_NAME \
    --region REGION \
    --instance-selection-machine-types MACHINE_TYPE,MACHINE_TYPE,...

Replace the following:

INSTANCE_GROUP_NAME: the name of the MIG.
REGION: the region where the MIG is located.
MACHINE_TYPE: the machine types that you want to configure in the MIG.

REST

To add multiple machine types to an existing MIG, make a PATCH request to the regionInstanceGroupManagers.patch method.

PATCH https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/instanceGroupManagers/INSTANCE_GROUP_NAME

{
  "instanceFlexibilityPolicy": {
    "instanceSelections": {
    "INSTANCE_SELECTION": {
        "machineTypes": [
          "MACHINE_TYPE_1",
          "MACHINE_TYPE_2"
          ...
        ]
      }
    }
  }
}

Replace the following:

PROJECT_ID: your project ID.
REGION: the region where the MIG is located.
INSTANCE_GROUP_NAME: the name of the MIG.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

Add multiple machine types and preferences

Console

In the Google Cloud console, go to the Instance groups page.

Go to Instance groups
Click the name of the MIG in which you want to set multiple machine types.
Click Edit.
Click Instance flexibility to expand the section.
In the Instance selections section, click Add selections.

The Instance selections window opens. Repeat the following steps for each instance selection that you want to add in the MIG.
1. Click Add instance selection.
2. In the New instance selection section, do the following:
  1. In the Name field, enter a name for the instance selection.
  2. In the Rank field, enter the order of preference among the instance selections that you add for the MIG.
  3. In the Machine types section, click Add machine type, select a machine type that you want to add in the instance selection, and then click Done.
    
    Repeat this step for each machine type that you want to add to the instance selection.
  4. After you complete adding the machine types, click Done.
After you complete adding the instance selections, click Done.
Click Save.

gcloud

To add multiple machine types and preferences to an existing MIG, use the instance-groups managed update command

gcloud compute instance-groups managed update INSTANCE_GROUP_NAME \
    --region REGION \
    --instance-selection "name=INSTANCE_SELECTION_1,machine-type=MACHINE_TYPE_1,machine-type=MACHINE_TYPE_2,rank=RANK_1" \
    --instance-selection "name=INSTANCE_SELECTION_2,machine-type=MACHINE_TYPE_3,machine-type=MACHINE_TYPE_4,rank=RANK_2"

Replace the following:

INSTANCE_GROUP_NAME: the name of the MIG.
REGION: the region where the MIG is located.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

REST

To add multiple machine types and preferences to an existing MIG, make a PATCH request to the regionInstanceGroupManagers.patch method.

PATCH https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/instanceGroupManagers/INSTANCE_GROUP_NAME

{
  "instanceFlexibilityPolicy": {
    "instanceSelections": {
      "INSTANCE_SELECTION_1": {
        "machineTypes": [
          "MACHINE_TYPE_1",
          "MACHINE_TYPE_2"
        ],
        "rank": RANK_1
      },
      "INSTANCE_SELECTION_2": {
        "machineTypes": [
          "MACHINE_TYPE_3",
          "MACHINE_TYPE_4"
        ],
        "rank": RANK_2
      }
    }
  }
}

Replace the following:

PROJECT_ID: your project ID.
REGION: the region where the MIG is located.
INSTANCE_GROUP_NAME: the name of the MIG.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

Add multiple machine types, preferences, and additional overrides

Console

In the Google Cloud console, go to the Instance groups page.

Go to Instance groups
Click the name of the MIG in which you want to set multiple machine types.
Click Edit.
Click Instance flexibility to expand the section.
In the Instance selections section, click Add selections.

The Instance selections window opens. Repeat the following steps for each instance selection that you want to add in the MIG.
1. Click Add instance selection.
2. In the New instance selection section, do the following:
  1. In the Name field, enter a name for the instance selection.
  2. In the Rank field, enter the order of preference among the instance selections that you add for the MIG.
  3. In the Machine types section, click Add machine type, select a machine type that you want to add in the instance selection, and then click Done.
    
    Repeat this step for each machine type that you want to add to the instance selection.
  4. If you want to override the minimum CPU platform specified in the instance template, then select the Override CPU platform for this selection checkbox. In the CPU platform list, select the platform that you want to use for the instance selection.
  5. If you want to override the disk configuration specified in the instance template or to attach a storage, then select the Override disks checkbox.
    - To override the boot disk, in the Boot disk section, click Change, and follow the prompts.
    - To attach a storage, click Add new disk or Attach existing disk, and follow the prompts.
  6. After you complete adding the machine types and the overrides, click Done.
After you complete adding the instance selections, click Done.
Click Save.

gcloud

To add multiple machine types, preferences, and instance property overrides to an existing MIG, use the beta instance-groups managed update command.

gcloud beta compute instance-groups managed update INSTANCE_GROUP_NAME \
    --region REGION \
    --instance-flexibility-policy= '{"instanceSelections": \
        {"INSTANCE_SELECTION_1":{"rank":RANK_1,"machineTypes":["MACHINE_TYPE_1","MACHINE_TYPE_2"],"minCpuPlatform":"MIN_CPU_PLATFORM_1","disks":[{"device-name":"DEVICE_NAME_1","boot":true,"initializeParams":{"sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE_NAME"}}]}, \
        "INSTANCE_SELECTION_2":{"rank":RANK_2,"machineTypes":["MACHINE_TYPE_3","MACHINE_TYPE_4"],"minCpuPlatform":"MIN_CPU_PLATFORM_2","disks":[{"device-name":"DEVICE_NAME_2","boot":true,"initializeParams":{"sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE_NAME"}}]}}}'

Replace the following:

INSTANCE_GROUP_NAME: the name of the MIG.
REGION: the region where the MIG is located.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
MIN_CPU_PLATFORM: the minimum CPU platform for the instances.
DEVICE_NAME: the device name for the disk.
IMAGE_PROJECT: the project ID of the source image.
IMAGE_NAME: the name of the source image.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

REST

To add multiple machine types, preferences, and instance property overrides to an existing MIG, make a PATCH request to the beta regionInstanceGroupManagers.patch method.

PATCH https://compute.googleapis.com/compute/beta/projects/PROJECT_ID/regions/REGION/instanceGroupManagers/INSTANCE_GROUP_NAME

{
  "instanceFlexibilityPolicy": {
    "instanceSelections": {
      "INSTANCE_SELECTION_1": {
        "machineTypes": [
          "MACHINE_TYPE_1",
          "MACHINE_TYPE_2"
        ],
        "minCpuPlatform": "MIN_CPU_PLATFORM_1",
        "disks": [
          {
            "deviceName": "DEVICE_NAME_1",
            "initializeParams": {
              "sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE_NAME"
            },
            "boot": true
          }
        ],
        "rank": RANK_1
      },
      "INSTANCE_SELECTION_2": {
        "machineTypes": [
          "MACHINE_TYPE_3",
          "MACHINE_TYPE_4"
        ],
        "minCpuPlatform": "MIN_CPU_PLATFORM_2",
        "disks": [
          {
            "deviceName": "DEVICE_NAME_2",
            "initializeParams": {
              "sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE_NAME"
            },
            "boot": true
          }
        ],
        "rank": RANK_2
      }
    }
  }
}

Replace the following:

PROJECT_ID: your project ID.
REGION: the region where the MIG is located.
INSTANCE_GROUP_NAME: the name of the MIG.
INSTANCE_SELECTION: the name of the list of machine types.
MACHINE_TYPE: the machine types that you want to configure in the MIG.
MIN_CPU_PLATFORM: the minimum CPU platform for the instances.
DEVICE_NAME: the device name for the disk.
IMAGE_PROJECT: the project ID of the source image.
IMAGE_NAME: the name of the source image.
RANK: a number representing your order of preference for instance selection. A lower value means a higher preference.

Example for YAML file to configure instance flexibility

You can use a YAML or JSON file to configure the instance flexibility policy. To do so, use the --flags-file flag in your gcloud CLI command and specify the filename. For example, use --flags-file=FILE_NAME.YAML.

The following is an example of YAML file:

--instance-flexibility-policy:
  instanceSelections:
    first-preference:
      rank: 1
      machineTypes:
        - n2-standard-8
      minCpuPlatform: "Intel Ice Lake"
      disks:
        - deviceName: data-disk
          boot: false
          initializeParams:
            sourceImage: projects/debian-cloud/global/images/debian-12
            diskType: pd-ssd

What's next

Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.

Last updated 2026-06-09 UTC.

Add instance flexibility Stay organized with collections Save and categorize content based on your preferences.

Before you begin

Console

gcloud

Terraform

REST

Create a MIG with instance flexibility

Create a MIG with multiple machine types

Console

gcloud

Terraform

REST

Create a MIG with multiple machine types and preferences

Console

gcloud

Terraform

REST

Create a MIG with multiple machine types, preferences, and additional overrides

Console

gcloud

Terraform

REST

Add instance flexibility to an existing MIG

Add multiple machine types

Console

gcloud

REST

Add multiple machine types and preferences

Console

gcloud

REST

Add multiple machine types, preferences, and additional overrides

Console

gcloud

REST

Example for YAML file to configure instance flexibility

What's next

Add instance flexibility