> ## Documentation Index
> Fetch the complete documentation index at: https://arklowdocs.io/llms.txt
> Use this file to discover all available pages before exploring further.

# GCP autoscaler floor

The **GCP managed instance group** target connects Arklow to an existing Google Cloud autoscaler. Arklow changes the permitted range, and the autoscaler chooses the group's live target size from its own signals.

## Configuration

Along with the [shared group fields](/resources/scale-targets/gcp/index#shared-configuration), enter the **Autoscaler** name attached to the managed instance group.

The target's **Minimum replicas** and **Maximum replicas** are written to the autoscaler's `minNumReplicas` and `maxNumReplicas` settings.

## Required permissions

The selected GCP Service Account credential needs:

```text theme={null}
compute.instanceGroupManagers.get
compute.autoscalers.get
compute.autoscalers.update
```

You can place these permissions in a custom role scoped to the project containing the group.

## Add an autoscaler target

<Steps>
  <Step title="Open scale targets">
    Go to [**Scale Targets**](https://app.arklow.io/dashboard/scale-targets), click **New scale target**, and select **GCP managed instance group**.
  </Step>

  <Step title="Identify the group">
    Enter its project, location type, location, instance group manager, and autoscaler name.
  </Step>

  <Step title="Select authentication">
    Choose the GCP Service Account credential with permission to read the group and update its autoscaler.
  </Step>

  <Step title="Select capacity">
    Choose the destination or shared pool served by the group.
  </Step>

  <Step title="Set the envelope">
    Enter the minimum and maximum replicas available to the GCP autoscaler.
  </Step>

  <Step title="Save">
    Create the target and confirm that the observed target size belongs to the expected group.
  </Step>
</Steps>