AddBackendServers - Server Load Balancer - Alibaba Cloud Documentation Center

Note If multiple identical Elastic Compute Service (ECS) instances are specified in a request, only the first ECS instance is added. The other ECS instances are ignored. If the backend server that you add is the same as one of the existing backend servers that are already associated with the listener, an error message is returned.

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
RegionId	String	No	cn-beijing	The ID of the region where the Classic Load Balancer (CLB) instance is deployed. You can call the DescribeRegions operation to query the most recent region list.
Action	String	Yes	AddBackendServers	The operation that you want to perform. Set the value to AddBackendServers.
LoadBalancerId	String	Yes	lb-2ze7o5h52g02kkzz******	The ID of the CLB instance.
BackendServers	String	No	[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168..", "Port":"80","Description":"test-112" },{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "172.166..", "Port":"80","Description":"test-113" }]	The list of backend servers that you want to add. Set the following parameters: ServerId: Required. This value must be a string. Enter the ID of an ECS instance, elastic network interface (ENI), or elastic container instance. If ServerId is set to the ID of an ENI or elastic container instance, Type is required. Weight: the weight of the backend server. Valid values: 0 to 100. Default value: 100. If the value is set to 0, no requests are forwarded to the backend server. Description: Optional. The description of the backend server. This value must be a string. The description must be 1 to 80 characters in length, and can contain letters, digits, hyphens (-), forward slashes (/), periods (.), and underscores (_). Type: the type of the backend server. Valid values: ecs (default): an ECS instance eni: an ENI eci: an elastic container instance Note You can specify ENIs and elastic container instances as the backend servers only for high-performance CLB instances. ServerIp: the IP address of the ECS instance, ENI, or elastic container instance Port: the backend port Examples: ECS instance: `[{ "ServerId": "i-xxxxxxxxx", "Weight": "100", "Type": "ecs", "Port":"80","Description":"test-112" }]` ENI: `[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168..", "Port":"80","Description":"test-112" }]` ENI with multiple IP addresses: `[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168..", "Port":"80","Description":"test-113" },{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "172.166..", "Port":"80","Description":"test-113" }]` Elastic container instance: `[{ "ServerId": "eci-xxxxxxxxx", "Weight": "100", "Type": "eci", "ServerIp": "192.168..", "Port":"80","Description":"test-114" }]` Note The backend servers that you add to a CLB instance must be in the Running state. You can add at most 20 backend servers to a CLB instance in each request.

Response parameters


Parameter	Type	Example	Description
LoadBalancerId	String	lb-2ze7o5h52g02kkzz****	The ID of the CLB instance.
RequestId	String	34B82C81-F13B-4EEB-99F6-A048C67CC830	The ID of the request.
BackendServers	Array of BackendServer		The list of backend servers.
BackendServer
Type	String	ecs	The type of the backend server. Valid values: ecs (default): an ECS instance eni: an ENI eci: an elastic container instance
Weight	String	100	The weight of the backend server. Valid values: 0 to 100. Default value: 100. If the value is set to 0, no requests are forwarded to the backend server.
Description	String	BackendServer	The description of the backend server.
ServerId	String	i-2zej4lxhjoq1icu*****	The ID of the ECS instance, ENI, or elastic container instance.

Examples

Sample requests

http(s)://[Endpoint]/?RegionId=cn-beijing
&Action=AddBackendServers
&LoadBalancerId=lb-2ze7o5h52g02kkzz******
&BackendServers=[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168.**.**", "Port":"80","Description":"test-112" },{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "172.166.**.**", "Port":"80","Description":"test-113" }]
&Common request parameters

Sample success responses

XML format

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

<AddBackendServersResponse>
    <LoadBalancerId>lb-2ze7o5h52g02kkzz****</LoadBalancerId>
    <RequestId>34B82C81-F13B-4EEB-99F6-A048C67CC830</RequestId>
    <BackendServers>
        <Type>ecs</Type>
        <Weight>100</Weight>
        <Description>BackendServer</Description>
        <ServerId>i-2zej4lxhjoq1icu*****</ServerId>
    </BackendServers>
</AddBackendServersResponse>

JSON format

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

{
  "LoadBalancerId" : "lb-2ze7o5h52g02kkzz****",
  "RequestId" : "34B82C81-F13B-4EEB-99F6-A048C67CC830",
  "BackendServers" : [ {
    "Type" : "ecs",
    "Weight" : "100",
    "Description" : "BackendServer",
    "ServerId" : "i-2zej4lxhjoq1icu*****"
  } ]
}

Error codes


HttpCode	Error code	Error message	Description
400	InvalidParameter	The specified load balancer does not support the network type of the ECS instance.	The error message returned because the CLB instance does not support ECS instances of the specified type. Change the type and try again.
400	Mismatched.ZoneId	The zone of the server is not matched with the cloud box loadbalancer.	The error message returned because the server and the CLB instance that is connected to a cloud box are deployed in different zones.
400	BackendServerProcessing	Backend Server is adding, please try again later.	The error message returned because the backend server is being added. Try again later.
400	InvalidBackendServers.ServerIpConflict	%s.	The error message returned because a backend server that uses the same TunnelId and RsIp configurations exists.
400	OperationUnsupported.AddBackendServers	This type of backend server is not allowed to attached to singleTunnel or anyTunnel lb.	The error message returned because CLB instances of the Single Tunnel and Any Tunnel types do not support the specified type of backend server.
400	IncorrectStatus.RSByPassToas	%s.	The error message returned because the BypassToa parameter of the specified backend server is set to an invalid value.
400	OperationFailed.ActionNotSupport	The loadbalancer does not support such action.	The error message returned because the CLB instance does not support the operation.
400	NetworkConflict	%s.	The error message returned because configurations of the vServer group are inconsistent with the configurations of the ECS instance.

For a list of error codes, visit the API Error Center.