Method: instanceGroupManagers.resize

Resizes the managed instance group. If you increase the size, the group creates new instances using the current instance template. If you decrease the size, the group deletes instances. The resize operation is marked DONE when the resize actions are scheduled even if the group has not yet added or deleted any instances. You must separately verify the status of the creating or deleting actions with the listmanagedinstances method.

When resizing down, the instance group arbitrarily chooses the order in which VMs are deleted. The group takes into account some VM attributes when making the selection including:

  • The status of the VM instance.
  • The health of the VM instance.
  • The instance template version the VM is based on.
  • For regional managed instance groups, the location of the VM instance.

This list is subject to change.

If the group is part of a backend service that has enabled connection draining, it can take up to 60 seconds after the connection draining duration has elapsed before the VM instance is removed or deleted.

HTTP request

POST https://compute.googleapis.com/compute/v1/projects/{project}/zones/{zone}/instanceGroupManagers/{resourceId}/resize

The URL uses gRPC Transcoding syntax.

Path parameters

Parameters
project

string

Project ID for this request.

zone

string

The name of the zone where the managed instance group is located.

resourceId

string

The name of the managed instance group.

Authorization requires the following IAM permission on the specified resource instanceGroupManager:

  • compute.instanceGroupManagers.update

Query parameters

Parameters
requestId

string

An optional request ID to identify requests. Specify a unique request ID so that if you must retry your request, the server will know to ignore the request if it has already been completed.

For example, consider a situation where you make an initial request and the request times out. If you make the request again with the same request ID, the server can check if original operation with the same request ID was received, and if so, will ignore the second request. This prevents clients from accidentally creating duplicate commitments.

The request ID must be a valid UUID with the exception that zero UUID is not supported (00000000-0000-0000-0000-000000000000).

size

integer

The number of running instances that the managed instance group should maintain at any given time. The group automatically adds or removes instances to maintain the number of instances specified by this parameter.

Request body

The request body must be empty.

Response body

If successful, the response body contains data with the following structure:

Represents an Operation resource.

Google Compute Engine has three Operation resources:

You can use an operation resource to manage asynchronous API requests. For more information, read Handling API responses.

Operations can be global, regional or zonal.

  • For global operations, use the globalOperations resource.
  • For regional operations, use the regionOperations resource.
  • For zonal operations, use the zonalOperations resource.

For more information, read