ModifyVServerGroupBackendServers - Server Load Balancer - Alibaba Cloud Documentation Center

Replaces the backend servers in a server group.

Operation description

You can call this operation to replace the backend servers in a specified vServer group. To modify the configurations of the backend servers, such as their weights, you can call the SetVServerGroupAttribute operation.

Debugging

OpenAPI Explorer automatically calculates the signature value. For your convenience, we recommend that you call this operation in OpenAPI Explorer.

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	WRITE	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 list of backend servers that you want to replace in the vServer group. You can specify at most 20 backend servers for a vServer group in each call. ServerId: required. The ID of the Elastic Compute Service (ECS) instance or elastic network interface (ENI) that serves as a backend server. This parameter must be of the STRING type. Port: required. The port that is used by the backend server. This parameter must be of the INTEGER type. Valid values: 1 to 65535. Weight: required. The weight of the backend server. This parameter must be of the INTEGER type. Valid values: 0 to 100. Description: optional. The description of the backend server. This parameter must be of the STRING type. 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 backend server. This parameter must be of the STRING type. Valid values: ecs: an ECS instance. This is the default value. eni: an ENI. ServerIp: the IP address of the ECS instance or ENI. Examples: An ECS instance: `[{ "ServerId": "i-xxxxxxxxx", "Weight": "100", "Type": "ecs", "Port":"80","Description":"test-112" }]` An ENI: `[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168..", "Port":"80","Description":"test-112" }]` An ENI with multiple IP addresses: `[{ "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" }]`	[{ "ServerId": "i-xxxxxxxxx", "Weight": "100", "Type": "ecs", "Port":"80","Description":"test-112" }]
NewBackendServers	string	No	The list of new backend servers that you want to use to replace those in the vServer group. You can specify at most 20 backend servers for a vServer group in each call. ServerId: required. The ID of the ECS instance or ENI that serves as a backend server. This parameter must be of the STRING type. Port: required. The port that is used by the backend server. This parameter must be of the INTEGER type. Valid values: 1 to 65535. Weight: required. The weight of the backend server. This parameter must be of the INTEGER type. Valid values: 0 to 100. Description: optional. The description of the backend server. This parameter must be of the STRING type. The description can contain letters, digits, hyphens (-), forward slashes (/), periods (.),and underscores (_). Type: the type of backend server. This parameter must be of the STRING type. Valid values: ecs: an ECS instance. This is the default value. eni: an ENI. ServerIp: the IP address of the ECS instance or ENI. Examples: An ECS instance: `[{ "ServerId": "i-xxxxxxxxx", "Weight": "100", "Type": "ecs", "Port":"80","Description":"test-112" }]` An ENI: `[{ "ServerId": "eni-xxxxxxxxx", "Weight": "100", "Type": "eni", "ServerIp": "192.168..", "Port":"80","Description":"test-112" }]` An ENI with multiple IP addresses: `[{ "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" }]`	[{ "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 ID of the request.	9DEC9C28-AB05-4DDF-9A78-6B08EC9CE18C
BackendServers	object []	The list of backend servers.
Type	string	The type of backend server. Valid values: ecs: an ECS instance. This is the default value. eni: an ENI.	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

see changesets

Change item	Change content
Error Codes	The Error code has changed.
	Error Codes 400 change