AddBackendServers-阿里云帮助中心

Operation description

Note

If you add multiple identical ECS instances in a single request, the system processes only the first one and ignores subsequent identical instances. You cannot add new backend servers that duplicate existing servers under the same listener, because an error will occur.

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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

slb:AddBackendServers

update

*LoadBalancer

acs:slb:{#regionId}:{#accountId}:loadbalancer/{#LoadBalancerId}

*Instance

acs:ecs:{#regionId}:{#accountId}:instance/{#InstanceId}

None

Request parameters

Parameter	Type	Required	Description	Example
RegionId	string	No	The ID of the region where the Server Load Balancer (SLB) instance resides. Call DescribeRegions to query the region ID.	cn-beijing
LoadBalancerId	string	Yes	The ID of the Classic Load Balancer (CLB) instance.	lb-2ze7o5h52g02kkzz******
BackendServers	string	No	The list of backend servers to add. It contains the following parameters: ServerId: String type, required. The instance ID of the backend server. It can be an ECS instance ID, an ENI instance ID, or an ECI instance ID. If the ServerId parameter is an ENI instance ID or an ECI instance ID, the Type parameter is required. Weight: The weight of the backend server. Valid values: 0 to 100. Default value: 100. If the value is 0, the system does not forward requests to the backend server. Description: String type, optional. The description of the backend server. The description can contain 1 to 80 characters. It supports Chinese characters, letters, digits, hyphens (-), forward slashes (/), periods (.), and underscores (_). Type: The type of the backend server. Valid values: ecs: ECS instance (default). eni: Elastic Network Interface (ENI) instance. eci: Elastic Container Instance (ECI). Note Only guaranteed-performance instances support adding ENI and ECI backend servers. ServerIp: The instance IP address of the ENI or ECI. Port: The backend port that accepts requests. Examples: Attach an ECS instance: `[{ "ServerId": "i-xxxxxxxxx", "Weight": "100", "Type": "ecs", "Port":"80","Description":"test-112" }]` Attach an ENI: `[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168..", "Port":"80","Description":"test-112" }]` Attach multiple ENI 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" }]` Attach an ECI: `[{ "ServerId": "eci-xxxxxxxxx", "Weight": "100", "Type": "eci", "ServerIp": "192.168..", "Port":"80","Description":"test-114" }]` Note Only running backend servers can be added to a Server Load Balancer (SLB) instance. Each call can add a maximum of 20 backend servers.	[{ "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" }]

Response elements

Element	Type	Description	Example
	object
LoadBalancerId	string	The ID of the Server Load Balancer (SLB) instance.	lb-2ze7o5h52g02kkzz****
RequestId	string	The request ID.	34B82C81-F13B-4EEB-99F6-A048C67CC830
BackendServers	object
BackendServer	array<object>	The list of backend servers.
	object
Type	string	The type of the backend server. Valid values: ecs: ECS instance (default). eni: Elastic Network Interface (ENI) instance. eci: Elastic Container Instance (ECI).	ecs
Weight	string	The weight of the backend server. Valid values: 0 to 100. Default value: 100. If the value is 0, the system does not forward requests to the backend server.	100
Description	string	The description of the backend server. Note If you do not set Description, the parameter is not returned.	The description of the backend server.
ServerId	string	The ID of the ECS, ENI, or ECI instance.	i-2zej4lxhjoq1icu*****

Examples

Success response

JSON format

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

Error codes

HTTP status code	Error code	Error message	Description
400	InvalidParameter	The specified load balancer does not support the network type of the ECS instance.
400	Mismatched.ZoneId	The zone of the server is not matched with the cloud box loadbalancer.
400	BackendServerProcessing	Backend Server is adding, please try again later.
400	InvalidBackendServers.ServerIpConflict	%s.
400	OperationUnsupported.AddBackendServers	This type of backend server is not allowed to attached to singleTunnel or anyTunnel lb.
400	IncorrectStatus.RSByPassToas	%s.
400	OperationFailed.ActionNotSupport	The loadbalancer does not support such action.
400	NetworkConflict	%s.
400	SystemBusy	The system is busy.	System Busy

See Error Codes for a complete list.

Release notes

See Release Notes for a complete list.