RemoveInstances - Auto Scaling - Alibaba Cloud Documentation Center

Removes one or more instances from a scaling group. If your scaling group is enabled and contains no ongoing scaling activities, you can call the RemoveInstances operation to remove instances that you no longer require from the scaling group.

Operation description

Before you call this operation, make sure that the following requirements are met:
- The scaling group is in the Active state.
- No scaling activity is in progress within the scaling group.

Note If no scaling activity is in progress within the scaling group, you can call the operation even within the cooldown period.

If an ECS instance is automatically created by Auto Scaling, or if an ECS instance is manually added to a scaling group and managed by the scaling group, the ECS instance is stopped in economical mode or is released after the instance is removed from the scaling group.
If an ECS instance is manually added to a scaling group and is not managed by the scaling group, the ECS instance is not stopped or released after the instance is removed from the scaling group.
If the difference between the number of existing ECS instances specified by the TotalCapacity parameter and the number of ECS instances that you call this operation to remove is less than the value of the MinSize parameter, the call fails.

A successful call only means that Auto Scaling accepts the request. The scaling activity may still fail. You can obtain the status of a scaling activity based on the value of the ScalingActivityId parameter in the response.

Debugging

You can run this interface directly in OpenAPI Explorer, saving you the trouble of calculating signatures. After running successfully, OpenAPI Explorer can automatically generate SDK code samples.

Debug

Authorization information

The following table shows the authorization information corresponding to the API. The authorization information can be used in the Action policy element to grant a RAM user or RAM role the permissions to call this API operation. Description:

Operation: the value that you can use in the Action element to specify the operation on a resource.
Access level: the access level of each operation. The levels are read, write, and list.
Resource type: the type of the resource on which you can authorize the RAM user or the RAM role to perform the operation. Take note of the following items:
- The required resource types are displayed in bold characters.
- If the permissions cannot be granted at the resource level, All Resources is used in the Resource type column of the operation.
Condition Key: the condition key that is defined by the cloud service.
Associated operation: other operations that the RAM user or the RAM role must have permissions to perform to complete the operation. To complete the operation, the RAM user or the RAM role must have the permissions to perform the associated operations.

Operation	Access level	Resource type	Condition key	Associated operation
ess:DetachInstances	update	ScalingGroup acs:ess:{#regionId}:{#accountId}:scalinggroup/{#ScalingGroupId}	none	none

Request parameters

Parameter	Type	Required	Description	Example
ScalingGroupId	string	Yes	The ID of the scaling group.	asg-bp18p2yfxow2dloq****
RemovePolicy	string	No	The action subsequent to the removal of the Elastic Compute Service (ECS) instances. Valid values: recycle: The ECS instances enter the Economical Mode. Note** This setting is applicable only if you set `ScalingPolicy` to `recycle`. release: The ECS instances are released. ScalingPolicy of the CreateScalingGroup operation specifies the reclaim mode of the scaling group while RemovePolicy of the RemoveInstances operation specifies the subsequent action when an ECS instance is removed from the scaling group. Examples: If you set ScalingPolicy and RemovePolicy to recycle, the ECS instances enter the Economical Mode when they are removed. If you set ScalingPolicy to recycle and RemovePolicy to release, the ECS instances are released when they are removed. If you set ScalingPolicy to release and RemovePolicy to recycle, the ECS instances are released when they are removed. If you set ScalingPolicy and RemovePolicy to release, the ECS instances are released when they are removed. Default value: release.	release
DecreaseDesiredCapacity	boolean	No	Specifies whether to adjust the expected number of ECS instances in the scaling group. Valid values: true: After ECS instances are removed from the scaling group, the expected number of ECS instances in the scaling group decreases. false: After ECS instances are removed from the scaling group, the expected number of ECS instances in the scaling group remains unchanged. Default value: true.	true
IgnoreInvalidInstance	boolean	No	Specifies whether to ignore invalid instances when you remove a batch of instances from the scaling group. Valid values: true: ignores invalid instances. If invalid instances exist and valid instances are deleted, the corresponding scaling activity enters the Warning state. You can check the scaling activity details to view the invalid instances that are ignored. false: does not ignore invalid instances. If invalid instances exist in the batch of instances that you want to remove from the scaling group, an error is reported. Default value: false.	false
InstanceIds	array	Yes	The IDs of the ECS instances that you want to remove from the scaling group.
	string	Yes	The ID of the ECS instance that you want to remove from the scaling group.	i-28wt4****
RegionId	string	No	The region ID of the scaling group.	cn-qingdao
ClientToken	string	No	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.	123e4567-e89b-12d3-a456-42665544****
StopInstanceTimeout	integer	No	The period of time that is required by the Elastic Compute Service (ECS) instance to enter the Stopped state during the scale-in process. Unit: seconds. Valid values: 30 to 240. Note By default, this parameter inherits the value of StopInstanceTimeout specified in the CreateScalingGroup or ModifyScalingGroup operation. You can also specify a different value for this parameter in the RemoveInstances operation. This parameter takes effect only if you set RemovePolicy to release. If you specify this parameter, the system proceeds with the scale-in process only after the period of time specified by StopInstanceTimeout ends. In this case, the scale-in operation continues regardless of whether the ECS instance enters the Stopped state or not. If you do not specify this parameter, the system proceeds with the scale-in process only after the ECS instance enters the Stopped state. If the ECS instance fails to enter the Stopped state, the scale-in process rolls back, and the scale-in operation is considered as failed.	60

Response parameters

Parameter	Type	Description	Example
	object
ScalingActivityId	string	The ID of the scaling activity.	asa-bp175o6f6ego3r2j****
RequestId	string	The request ID.	473469C7-AA6F-4DC5-B3DB-A3DC0DE3C83E

Examples

Sample success responses

JSONformat

{
  "ScalingActivityId": "asa-bp175o6f6ego3r2j****",
  "RequestId": "473469C7-AA6F-4DC5-B3DB-A3DC0DE3C83E"
}

Error codes

HTTP status code	Error code	Error message
500	InternalError	The request processing has failed due to some unknown error, exception or failure.

For a list of error codes, visit the Service error codes.

Change history

Change time	Summary of changes	Operation
2024-10-16	The Error code has changed. The request parameters of the API has changed	View Change Details
2024-05-21	The Error code has changed. The request parameters of the API has changed	View Change Details