All Products
Search

This Product

    Auto Scaling:AttachAlbServerGroups

    Document Center

    Auto Scaling:AttachAlbServerGroups

    Last Updated:Aug 28, 2026

    Attaches Application Load Balancer (ALB) server groups to a scaling group. After ALB server groups are attached, Auto Scaling automatically adjusts computing capacity based on workload changes and dynamically distributes traffic to improve application stability and performance.

    Try it now

    Try this API in OpenAPI Explorer, no manual signing needed. Successful calls auto-generate SDK code matching your parameters. Download it with built-in credential security for local usage.

    Test

    RAM authorization

    The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

    • Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.

    • API: The API that you can call to perform the action.

    • Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.

    • Resource type: The type of the resource that supports authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.

      • For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.

      • For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.

    • Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.

    • Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

    Action

    Access level

    Resource type

    Condition key

    Dependent action

    ess:AttachAlbServerGroups

    update

    *ScalingGroup

    acs:ess:{#regionId}:{#accountId}:scalinggroup/{#ScalingGroupId}

    		 None None

    Request parameters

    Parameter

    Type

    Required

    Description

    Example
    RegionId

    string

    Yes

    The region ID of the scaling group.

    Examples: cn-hangzhou and cn-shanghai. For more information about regions and zones, see Regions and zones.

    cn-hangzhou
    ScalingGroupId

    string

    Yes

    The ID of the scaling group.

    asg-bp18p2yfxow2dloq****
    ClientToken

    string

    No

    The client token that ensures the idempotence of the request.

    You can use the client to generate the token, but you must ensure 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 Ensure idempotence.

    123e4567-e89b-12d3-a456-42665544****
    ForceAttach

    boolean

    No

    Specifies whether to add existing Elastic Compute Service (ECS) instances or elastic container instances in the scaling group to the new ALB server group. Valid values:

    • true: adds existing ECS instances or elastic container instances in the scaling group to the new ALB server group and returns the value of ScalingActivityId. You can use this value to check whether the instances are added to the ALB server group.

    • false: does not add existing ECS instances or elastic container instances in the scaling group to the new ALB server group.

    Default value: false.

    false
    AlbServerGroups

    array<object>

    Yes

    The information about the ALB server groups.

    object

    No

    Details of the ALB server group.

    AlbServerGroupId

    string

    Yes

    The ID of the ALB server group.

    You can attach only a limited number of ALB server groups to a scaling group. To view the predefined quota limit or manually request a quota increase, go to Quota Center.

    sgp-ddwb0y0g6y9bjm****
    Weight

    integer

    Yes

    The weight of an ECS instance or elastic container instance as a backend server in the ALB server group. Valid values: 0 to 100.

    A higher weight means the instance receives a larger share of traffic. A weight of zero means the instance receives no traffic.

    100
    Port

    integer

    Yes

    The port number of ECS instances or elastic container instances as backend servers in the ALB server group.

    Valid values: 1 to 65535.

    22

    Response elements

    Element

    Type

    Description

    Example

    object

    ScalingActivityId

    string

    The ID of the scaling activity in which the ALB server group is attached and existing instances in the scaling group are added to the ALB server group.

    Note

    This parameter is returned only if you set ForceAttach to true.

    asa-2ze6wxj8vsohn6j9****
    RequestId

    string

    The ID of the request.

    473469C7-AA6F-4DC5-B3DB-A3DC0DE3****

    Examples

    Success response

    JSON format

    {
  "ScalingActivityId": "asa-2ze6wxj8vsohn6j9****",
  "RequestId": "473469C7-AA6F-4DC5-B3DB-A3DC0DE3****"
}

    Error codes

    See Error Codes for a complete list.

    Release notes

    See Release Notes for a complete list.