Ends the timeout period of a lifecycle hook ahead of schedule.

Usage notes

If you set the LifecycleActionResult parameter for a lifecycle hook of a scaling group to CONTINUE in the operation, Auto Scaling continues to complete the scaling activity in the scaling group after the lifecycle hook times out. If you set the LifecycleActionResult parameter to ABANDON, Auto Scaling stops the scaling activity in the scaling group after the lifecycle hook times out.


OpenAPI Explorer automatically calculates the signature value. For your convenience, we recommend that you call this operation in OpenAPI Explorer. OpenAPI Explorer dynamically generates the sample code of the operation for different SDKs.

Request parameters


The operation that you want to perform. Set the value to CompleteLifecycleAction.


The ID of the lifecycle hook.


The token of the lifecycle hook. You can obtain the token by using a Message Service (MNS) queue or an MNS topic that is specified for the lifecycle hook.


The action that you want Auto Scaling to perform after the lifecycle hook times out. Valid values:

  • CONTINUE: Auto Scaling continues to respond to a scale-in or scale-out request.
  • ABANDON: Auto Scaling releases Elastic Compute Service (ECS) instances that are created during scale-out activities or removes ECS instances from the scaling group during scale-in activities.
  • ROLLBACK: For scale-in activities, Auto Scaling rejects the requests to release ECS instances but rolls back ECS instances. For scale-out activities, the ROLLBACK setting has the same effect as the ABANDON setting.

If you do not specify this parameter, Auto Scaling performs the action that is specified by the DefaultResult parameter after the lifecycle hook times out.

If multiple lifecycle hooks exist in a scaling group and the lifecycle hooks are triggered at the same time, the following rules apply:

  • For scale-in activities, when lifecycle hooks whose LifecycleActionResult parameter is set to ABANDON or ROLLBACK time out, other lifecycle hooks time out ahead of schedule.
  • For scale-in and scale-out activities, if you set the LifecycleActionResult parameter for all lifecycle hooks to CONTINUE, Auto Scaling performs the subsequent action only after the last lifecycle hook times out. The action that is performed by Auto Scaling varies based on the value that you specified for the LifecycleActionResult parameter of the last lifecycle hook that times out.

The client token that is used to ensure the idempotence of the request. You can use the client to generate the token, but you must make sure that the token is unique among different requests.

The token can contain only ASCII characters and cannot exceed 64 characters in length. For more information, see How to ensure idempotence.


The region ID of the scaling group.

Response parameters


The ID of the request.


Sample requests

&<Common request parameters>

Sample success responses

XML format

HTTP/1.1 200 OK


JSON format

HTTP/1.1 200 OK

  "RequestId" : "473469C7-AA6F-4DC5-B3DB-A3DC0DE3****"

Error codes

For a list of error codes, see Service error codes.

HTTP status code

Error code

Error message




The specified value of parameter is invalid.

The error message returned because the specified value of a parameter is invalid.



The specified lifecycleActionToken and lifecycleHookId you provided does not match any in process lifecycle action.

The error message returned because the value that you specified for the LifecycleActionToken parameter does not match the value that you specified for the LifecycleHookId parameter.