Remove Backend Servers from a GWLB Server Group - Server Load Balancer - Alibaba Cloud - Server Load Balancer

Removes backend servers from the server group of a Gateway Load Balancer (GWLB) instance.

Operation description

RemoveServersFromServerGroup is an asynchronous operation. After you send a request, the system returns a request ID and runs the task in the background.

You can call the ListServerGroups operation to query the status of a server group.
- If the server group is in the Configuring state, the server group is being modified.
- If the server group is in the Available state, the server group is running.
You can call the ListServerGroupServers operation to query the status of a backend server.
- If the backend server is in the Removing state, the backend server is being removed from the server group.
- If the backend server cannot be found, the backend server is no longer in the server group.

Note

If connection draining is enabled (ConnectionDrainEnabled set to true) for the server group, the removed backend server enters the Removing state before entering the Draining state. When the connection draining timeout period (ConnectionDrainTimeout) ends, the backend server is removed from the server group.
You can re-add the backend server to the server group before the connection draining timeout period ends. In this case, the server status changes from Draining to Adding, and then to Available after the server is added.

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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

gwlb:RemoveServersFromServerGroup

delete

*ServerGroup

acs:gwlb:{#regionId}:{#accountId}:servergroup/{#ServerGroupId}

Instance

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

NetworkInterface

acs:ecs:{#regionId}:{#accountId}:eni/{#ServerId}

ContainerGroup

acs:eci:{#regionId}:{#accountId}:containergroup/{#ServerId}

None

Request parameters

Parameter	Type	Required	Description	Example
ServerGroupId	string	Yes	The server group ID.	sgp-atstuj3rtoptyui****
Servers	array<object>	Yes	The backend servers that you want to remove. Note You can remove at most 200 backend servers in each call.
	object	No	The backend server.
Port	integer	No	The port used by the backend server. Valid values: 6081	6081
ServerId	string	Yes	The backend server ID. If the server group is of the Instance type, set this parameter to the IDs of servers of the Ecs, Eni, or Eci type. If the server group is of the Ip type, set ServerId to IP addresses.	i-bp67acfmxazb4p****
ServerIp	string	No	The IP address of the backend server.	192.168.xxx.xxx
ServerType	string	Yes	The type of the backend server. Valid values: Ecs: Elastic Compute Service (ECS) instance Eni: elastic network interface (ENI) Eci: elastic container instance Ip: IP address	Ecs
DryRun	boolean	No	Whether to perform only a dry run without performing the actual request. Valid values: true: performs only a dry run. The system checks the request for potential issues, including missing parameter values, incorrect request syntax, and service limits. If the request fails the dry run, an error code is returned. If the request passes the dry run, the `DryRunOperation` error code is returned. false (default): performs a dry run and then performs the actual request. If the request passes the dry run, a 2xx HTTP status code is returned and the operation is performed.	false
ClientToken	string	No	The client token that ensures the idempotence of the request. You can use the client to generate the token, but the token must be unique across different requests. The client token can contain only ASCII characters. Note If you do not specify this parameter, the system automatically uses the request ID as the client token. The request ID may be different for each request.	123e4567-e89b-12d3-a456-42665544****

Response elements

Element	Type	Description	Example
	object	The response parameters.
RequestId	string	The request ID.	54B48E3D-DF70-471B-AA93-08E683A1B45

Examples

Success response

JSON format

{
  "RequestId": "54B48E3D-DF70-471B-AA93-08E683A1B45"
}

Error codes

HTTP status code	Error code	Error message	Description
400	IncorrectStatus.BackendServer	The status of %s [%s] is incorrect.	The current operation cannot be performed on the server as its status is unavailable. Please check if the server is currently undergoing any other operations.
400	IncorrectStatus.ServerGroup	The status of %s [%s] is incorrect.	The status of %s [%s] is incorrect.
404	ResourceNotFound.BackendServer	The specified resource of %s is not found.	The specified backend server resource does not exist.
404	ResourceNotFound.ServerGroup	The specified resource of %s is not found.	The specified server group resource does not exist.

See Error Codes for a complete list.

Release notes

See Release Notes for a complete list.