Method: instanceGroupManagers.resizeAdvanced

Resizes the managed instance group with advanced configuration options like disabling creation retries. This is an extended version of the resize method.

If you increase the size of the instance group, 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, creatingWithoutRetries, or deleting actions with the get or listmanagedinstances method.

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


The URL uses gRPC Transcoding syntax.

Path parameters



Project ID for this request.



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



The name of the managed instance group.

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

  • compute.instanceGroupManagers.update

Query parameters



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).

Request body

The request body contains data with the following structure:

JSON representation
  "targetSize": integer,
  "noCreationRetries": boolean


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.



If this flag is true, the managed instance group attempts to create all instances initiated by this resize request only once. If there is an error during creation, the managed instance group does not retry create this instance, and we will decrease the targetSize of the request instead. If the flag is false, the group attempts to recreate each instance continuously until it succeeds.

This flag matters only in the first attempt of creation of an instance. After an instance is successfully created while this flag is enabled, the instance behaves the same way as all the other instances created with a regular resize request. In particular, if a running instance dies unexpectedly at a later time and needs to be recreated, this mode does not affect the recreation behavior in that scenario.

This flag is applicable only to the current resize request. It does not influence other resize requests in any way.

You can see which instances is being creating in which mode by calling the get or listManagedInstances API.

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 Global, Regional, and Zonal Resources.

JSON representation
  "id": string,
  "creationTimestamp": string,
  "name": string,
  "zone": string,
  "clientOperationId": string,
  "operationType": string,
  "targetLink": string,
  "targetId": string,
  "status": enum,
  "statusMessage": string,
  "user": </