Set a target distribution shape for VMs in a regional MIG

If you use a regional managed instance group (MIG), you can set that MIG's target distribution shape to one of the following options:

  • EVEN (default): the group creates and deletes VMs to achieve and maintain the same number of VMs across the selected zones. In an EVEN distribution, the number of VMs does not differ by more than 1 between any two zones. Recommended for highly available serving workloads.
  • BALANCED: the group prioritizes creation of VMs in zones where resources are available, while distributing VMs as evenly as possible across selected zones to minimize the impact of zonal failure. Recommended for highly available serving or batch workloads.
  • ANY: the group picks zones for creating VM instances to fulfill the requested number of VMs within present resource constraints and to maximize utilization of unused zonal reservations. Recommended for batch workloads that do not require high availability.
  • ANY SINGLE ZONE: the group creates all VM instances within a single zone. The zone is chosen based on hardware support, current resource and quota availability, and matching reservations. Recommended in combination with a compact instance placement policy for workloads that require extensive communication between VMs.

To use reserved VMs in a regional managed instance group, create identical reservations with the same name in each applicable zone. Then, target those reservations by name in the group's instance template.

To help you choose a shape, see the comparison table, use cases, and how distribution shapes work.

Set a target distribution shape when creating your regional MIG or update the target shape of an existing regional MIG.

Before you begin

  • 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.

    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.

  • If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.

  • 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.