AttachLoadBalancers - Auto Scaling - Alibaba Cloud Documentation Center

Attaches one or more Classic Load Balancer (CLB, formerly known as SLB) instances to a scaling group.

Description

Before you call this operation to attach a CLB instance to your scaling group, take note of the following items:

The CLB instance and the scaling group must belong to the same Alibaba Cloud account.
The CLB instance and the scaling group must reside in the same region.
The CLB instance must be in the Running state.
The CLB instance must be configured with at least one listener. Health check is enabled for the CLB instance.
The CLB instance and the scaling group must be in the same virtual private cloud (VPC) if their network type is VPC.
If the network type of the scaling group is VPC, the network type of the CLB instance is classic network, and the CLB backend server groups contain instances of the VPC network type, the instances and the scaling group must be in the same VPC.
You can attach only a limited number of CLB instances to a scaling group. For more information, see Limits.

Debugging

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


Parameter	Type	Required	Example	Description
Action	String	Yes	AttachLoadBalancers	The operation that you want to perform. Set the value to AttachLoadBalancers.
ScalingGroupId	String	Yes	asg-bp1avr6ensitts3w****	The ID of the scaling group.
ForceAttach	Boolean	No	false	Specifies whether to add all instances in the current scaling group to the backend server groups of the attached CLB instance. Valid values: true false Default value: false.
ClientToken	String	No	123e4567-e89b-12d3-a456-42665544****	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.
Async	Boolean	No	false	Specifies whether to perform asynchronous calls to attach CLB instances to the scaling group. Asynchronous calls ensure the transactional nature of operations. This means that the execution results take effect only if all operations are successfully performed. We recommend that you perform asynchronous calls. Valid values: true: performs asynchronous calls. In this case, the ID of the scaling activity is returned. false: does not perform asynchronous calls. Default value: false.
LoadBalancer.N	String	No	lb-2zeur05gfs****	The ID of CLB instance N that you want to attach to the scaling group. Valid values of N: 1 to 5.
LoadBalancerConfig.N.LoadBalancerId	String	No	147b46d767c-cn-qingdao-cm5****	The ID of the CLB instance.
LoadBalancerConfig.N.Weight	Integer	No	10	The weight of an Elastic Compute Service (ECS) instance as a backend server in the backend server groups of the attached CLB instance. If you increase the weight of an ECS instance, the number of access requests that are forwarded to the ECS instance also increases. If you set Weight to 0 for an ECS instance, no access requests are forwarded to the ECS instance. Valid values: 0 to 100.

Response parameters


Parameter	Type	Example	Description
ScalingActivityId	String	asa-bp140qd7mak8k63f****	The ID of the scaling activity. The value of this parameter is returned only if you set Async to true. You can call the DescribeScalingActivities operation to query the returned IDs of the scaling activities and view the execution status of the scaling activities.
RequestId	String	473469C7-AA6F-4DC5-B3DB-A3DC0DE3****	The ID of the request.

Examples

Sample requests

http(s)://ess.aliyuncs.com/?Action=AttachLoadBalancers
&ScalingGroupId=asg-bp1avr6ensitts3w****
&ForceAttach=false
&ClientToken=123e4567-e89b-12d3-a456-42665544****
&Async=false
&LoadBalancer=["lb-2zeur05gfs****"]
&LoadBalancerConfig=[{"LoadBalancerId":"147b46d767c-cn-qingdao-cm5****","Weight":10}]
&<Common request parameters>

Sample success responses

XML format

HTTP/1.1 200 OK
Content-Type:application/xml

<AttachLoadBalancersResponse>
    <ScalingActivityId>asa-bp140qd7mak8k63f****</ScalingActivityId>
    <RequestId>473469C7-AA6F-4DC5-B3DB-A3DC0DE3****</RequestId>
</AttachLoadBalancersResponse>

JSON format

HTTP/1.1 200 OK
Content-Type:application/json

{
  "ScalingActivityId" : "asa-bp140qd7mak8k63f****",
  "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	Description
403	Forbidden.Unauthorized	A required authorization for the specified action is not supplied.	Auto Scaling is not authorized to call the operation.
404	InvalidScalingGroupId.NotFound	The specified scaling group does not exist.	The specified scaling group does not exist within the Alibaba Cloud account.
400	QuotaExceeded.LoadBalancer	LoadBalancer quota exceeded in the scaling group "%s".	The maximum number of CLB instances that you can attach to the scaling group exceeds the upper limit.
404	InvalidLoadBalancerId.NotFound	The load balancer "%s" does not exist.	The specified CLB instance does not exist within the Alibaba Cloud account.
400	InvalidLoadBalancerId.RegionMismatch	The load balancer "%s" and the specified scaling group are not in the same Region.	The CLB instance and the scaling group do not reside in the same region.
400	IncorrectLoadBalancerStatus	The current status of the load balancer "%s" does not support this action.	The operation is not supported when the SLB instance is in the current state.
400	IncorrectLoadBalancerHealthCheck	The current health check type of the load balancer "%s" does not support this action.	The health check feature is not enabled for the CLB instance.
400	InvalidLoadBalancerId.VPCMismatch	The specified virtual switch and the instance in the load balancer "%s" are not in the same VPC.	The CLB instance and the scaling group do not reside in the same VPC.
400	QuotaExceeded.BackendServer	Backend server quota exceeded in the load balancer "%s".	The number of backend servers of the CLB instance exceeds the upper limit.
404	InvalidScalingConfigurationId.NotFound	The specified scaling configuration does not exist.	The scaling group has no scaling configuration that is enabled.