ModifyVServerGroupBackendServers - Server Load Balancer - Alibaba Cloud Documentation Center

Replaces backend servers in a vServer group.

Operation description

This operation can be used only to replace backend servers in a vServer group. To modify the attributes of backend servers, such as weights, call the SetVServerGroupAttribute operation.

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
slb:ModifyVServerGroupBackendServers	update	instance acs:ecs:{#regionId}:{#accountId}:instance/{#instanceId} loadbalancer acs:slb:{#regionId}:{#accountId}:loadbalancer/{#loadbalancerId}	slb:tag	none

Request parameters

Parameter	Type	Required	Description	Example
RegionId	string	Yes	The ID of the region where the Classic Load Balancer (CLB) instance is deployed.	cn-hangzhou
VServerGroupId	string	Yes	The ID of the vServer group.	rsp-cige6j****
OldBackendServers	string	No	The backend servers that you want to replace. Configure the following parameters: ServerId: required. The IDs of the backend servers. Specify the IDs in a string. You can specify the IDs of Elastic Compute Service (ECS) instances, elastic network interfaces (ENIs), and elastic container instances. If you set ServerId to the IDs of ENIs or elastic container instances, you must configure the Type parameter. Weight: the weight of the backend server. Valid values: 0 to 100. Default value: 100. If you set the weight of a backend server to 0, no requests are forwarded to the backend server. Description: optional. The description of the backend servers. Specify the description in 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): ECS instance eni: ENI eci: elastic container instance Note You can specify ENIs and elastic container instances as backend servers only for high-performance SLB instances. ServerIp: the IP address of the ENI or elastic container instance. Port: the backend port. Examples: Add an ECS instance: `[{ "ServerId": "i-xxxxxxxxx", "Weight": "100", "Type": "ecs", "Port":"80","Description":"test-112" }]` Add an ENI: `[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168..", "Port":"80","Description":"test-112" }]` Add an 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" }]` Add an elastic container instance `[{ "ServerId": "eci-xxxxxxxxx", "Weight": "100", "Type": "eci", "ServerIp": "192.168..", "Port":"80","Description":"test-114" }]` Note You can add only running backend servers to SLB instances. You can specify at most 20 backend servers in each call.	[{ "ServerId": "i-xxxxxxxxx", "Weight": "100", "Type": "ecs", "Port":"80","Description":"test-112" }]
NewBackendServers	string	No	The backend servers that you want to add to the vServer group. Configure the following parameters: ServerId: required. The IDs of the backend servers. Specify the IDs in a string. You can specify the IDs of ECS instances, ENIs, and elastic container instances. If you set ServerId to the IDs of ENIs or elastic container instances, you must configure the Type parameter. Weight: the weight of the backend server. Valid values: 0 to 100. Default value: 100. If you set the weight of a backend server to 0, no requests are forwarded to the backend server. Description: optional. The description of the backend servers. Specify the description in 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): ECS instance eni: ENI eci: elastic container instance Note You can specify ENIs and elastic container instances as backend servers only for high-performance SLB instances. ServerIp: the IP address of the ENI or elastic container instance. Port: the backend port. Examples: Add an ECS instance: `[{ "ServerId": "i-xxxxxxxxx", "Weight": "100", "Type": "ecs", "Port":"80","Description":"test-112" }]` Add an ENI: `[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168..", "Port":"80","Description":"test-112" }]` Add an 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" }]` Add an elastic container instance `[{ "ServerId": "eci-xxxxxxxxx", "Weight": "100", "Type": "eci", "ServerIp": "192.168..", "Port":"80","Description":"test-114" }]` Note You can add only running backend servers to SLB instances. You can specify at most 20 backend servers in each call.	[{ "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 parameters

Parameter	Type	Description	Example
	object
VServerGroupId	string	The ID of the vServer group.	rsp-cige6j****
RequestId	string	The request ID.	9DEC9C28-AB05-4DDF-9A78-6B08EC9CE18C
BackendServers	array<object>	The backend servers.
BackendServer	object
Type	string	The type of backend server. Valid values: ecs (default): ECS instance eni: ENI eci: elastic container instance	ecs
Weight	integer	The weight of the backend server.	100
Description	string	The description of the backend server.	Backend server description
Port	integer	The port that is used by the backend server.	70
ServerId	string	The ID of the ECS instance or ENI.	i-bp1ge5hrp****

Examples

Sample success responses

JSONformat

{
  "VServerGroupId": "rsp-cige6j****",
  "RequestId": "9DEC9C28-AB05-4DDF-9A78-6B08EC9CE18C",
  "BackendServers": {
    "BackendServer": [
      {
        "Type": "ecs",
        "Weight": 100,
        "Description": "Backend server description",
        "Port": 70,
        "ServerId": "i-bp1ge5hrp****"
      }
    ]
  }
}

Error codes

HTTP status code	Error code	Error message	Description
400	InvalidParameter	The specified BackendServers contain duplicated value of ServerID and Port.	The specified backend servers contain duplicate service IDs and ports.
400	Mismatched.ZoneId	The zone of the server is not matched with the cloud box loadbalancer.	-
400	InvalidBackendServers.ServerIpConflict	%s.	-
400	OperationUnsupported.ModifyVServerGroupBackendServers	This type of backend server is not allowed to attached to singleTunnel or anyTunnel lb.	-
400	IncorrectStatus.RSByPassToas	%s.	-
400	BackendServer.InvalidType	The specified Type is invalid.	-
400	BackendServer.ServerRegionIdNotEqual	The specified ServerRegionId must be equal.	-
400	OperationFailed.InvalidCen	The cen related with this loadbalancer is invalid.	-
400	IncorrectStatus.CenNotAssociated	The action is invalid because the loadbalancer is not associated with cen.	-
400	InvalidBackendServers.MissingCenBandWidth	The bandwidth is missing between loadbalancer and backendServers in cen.	-
400	InvalidBackendServers.VpcNotInCen	The BackendServers is not in the cen associated with the loadbalancer.	-
400	InvalidServerId.NotExist	The specified ServerId is not exist.	-
400	MissingParameter.ServerRegionId	The parameter ServerRegionId is required.	-
400	MissingParameter.VbrId	The parameter VbrId is required.	-
400	InvalidParameter.ServerRegionId	The parameter ServerRegionId is invalid for crossborder.	-
400	InvalidVbrId.NotInCen	The VbrId is not in the cen associated with the loadbalancer.	-
400	InvalidParameter.ServerRegionId	The specified ServerRegionId is invalid.	-
400	InvalidParameter.ZoneNotSupport	The zone does not support the parameter %s.	-
400	MasterSlaveServerConflict	The servers are conflict for MasterSlaveGroup.	-
400	NetworkConflict	%s.	-

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

Change history

Change time	Summary of changes	Operation
2023-09-08	The Error code has changed	View Change Details