doc-exports/docs/elb/api-ref/CreateMember.html

Adding a Backend Server

Function

This API is used to add a backend server.

Constraints

When you add backend servers, note the following:

• Two backend servers in the same backend server group must have different IP addresses and ports.

• If no subnets are specified during cloud server creation, IP as backend servers can be added. In this case, address must be set to an IPv4 address, the protocol of the backend server group must be TCP, HTTP, or HTTPS, and IP as a Backend must have been enabled for the load balancer.

• If a subnet is specified during cloud server creation, the subnet must be in the same VPC where the load balancer resides.

• If the backend server group supports IPv4/IPv6 dual stack, address can be an IPv4 address or an IPv6 address. If the backend server group supports only IPv4, address can only be an IPv4 address.

URI

POST /v3/{project_id}/elb/pools/{pool_id}/members

Table 1 Path Parameters

Parameter	Mandatory	Type	Description
pool_id	Yes	String	Specifies the ID of the backend server group.
project_id	Yes	String	Specifies the project ID.

Request Parameters

Table 2 Request header parameters

Parameter	Mandatory	Type	Description
X-Auth-Token	Yes	String	Specifies the token used for IAM authentication.

Table 3 Request body parameters

Parameter	Mandatory	Type	Description
member	Yes	CreateMemberOption object	Specifies the backend server.

Table 4 CreateMemberOption

Parameter	Mandatory	Type	Description
address	Yes	String	Specifies the private IP address bound to the backend server. If subnet_cidr_id is left blank, IP as a Backend is enabled. In this case, the IP address must be an IPv4 address. If subnet_cidr_id is not left blank, the IP address can be IPv4 or IPv6. It must be in the subnet specified by subnet_cidr_id and can only be bound to the primary NIC of the backend server. Minimum: 1 Maximum: 64
admin_state_up	No	Boolean	Specifies the administrative status of the backend server. The value can be true or false. Although this parameter can be used in the APIs for creating and updating backend servers, its actual value depends on whether cloud servers exist. If cloud servers exist, the value is true. Otherwise, the value is false.
name	No	String	Specifies the backend server name. Minimum: 0 Maximum: 255
project_id	No	String	Specifies the project ID. Minimum: 1 Maximum: 32
protocol_port	Yes	Integer	Specifies the port used by the backend server to receive requests. Minimum: 1 Maximum: 65535
subnet_cidr_id	No	String	Specifies the ID of the IPv4 or IPv6 subnet where the backend server resides. Note: The IPv4 or IPv6 subnet must be in the same VPC as the subnet of the load balancer. If this parameter is not passed, IP as a Backend has been enabled for the load balancer. In this case, IP as backend servers must use private IPv4 addresses, and the protocol of the backend server group must be TCP, HTTP, or HTTPS. Minimum: 1 Maximum: 36
weight	No	Integer	Specifies the weight of the backend server. Requests are routed to backend servers in the same backend server group based on their weights. The value ranges from 0 to 100, and the default value is 1. The larger the weight is, the higher proportion of requests the backend server receives. If the weight is set to 0, the backend server will not accept new requests. If lb_algorithm is set to SOURCE_IP, this parameter will not take effect.
availability_zone	No	String	Definition: Specifies the AZ of the backend server. Constraints: This parameter can be only set for IP as backend servers. If AZ affinity is enabled for the backend server group, this parameter must be set to a valid value for IP as backend servers. Range: AZs available for ECSs in the current region. Default value: N/A

Response Parameters

Status code: 201

Table 5 Response body parameters

Parameter	Type	Description
request_id	String	Specifies the request ID. The value is automatically generated.
member	Member object	Specifies the backend server.

Table 6 Member

Parameter	Type	Description
id	String	Specifies the backend server ID. Note: The value of this parameter is not the ID of the server but an ID automatically generated for the backend server that has already associated with the load balancer.
availability_zone	String	Definition: Specifies the AZ of the backend server. Default value: N/A
name	String	Specifies the backend server name.
project_id	String	Specifies the project ID of the backend server.
admin_state_up	Boolean	Specifies the administrative status of the backend server. The value can be true or false. Although this parameter can be used in the APIs for creating and updating backend servers, its actual value depends on whether cloud servers exist. If cloud servers exist, the value is true. Otherwise, the value is false.
subnet_cidr_id	String	Specifies the ID of the IPv4 or IPv6 subnet where the backend server resides. This parameter can be left blank, indicating that IP as a Backend has been enabled for the load balancer. In this case, IP addresses of these servers must be IPv4 addresses, and the protocol of the backend server group must be TCP, HTTP, or HTTPS. The IPv4 or IPv6 subnet must be in the same VPC as the subnet of the load balancer.
protocol_port	Integer	Specifies the port used by the backend server to receive requests. Minimum: 1 Maximum: 65535
weight	Integer	Specifies the weight of the backend server. Requests are routed to backend servers in the same backend server group based on their weights. The value ranges from 0 to 100, and the default value is 1. The larger the weight is, the higher proportion of requests the backend server receives. If the weight is set to 0, the backend server will not accept new requests. If lb_algorithm is set to SOURCE_IP, this parameter will not take effect. Minimum: 0 Maximum: 100
address	String	Specifies the private IP address bound to the backend server. If subnet_cidr_id is left blank, IP as a Backend is enabled. In this case, the IP address must be an IPv4 address. If subnet_cidr_id is not left blank, the IP address can be IPv4 or IPv6. It must be in the subnet specified by subnet_cidr_id and can only be bound to the primary NIC of the backend server.
ip_version	String	Specifies the IP version supported by the backend server. The value can be v4 (IPv4) or v6 (IPv6), depending on the value of address returned by the system.
operating_status	String	Specifies the health status of the backend server. The value can be one of the following: ONLINE: The backend server is running normally. NO_MONITOR: No health check is configured for the backend server group to which the backend server belongs. OFFLINE: The cloud server used as the backend server is stopped or does not exist.
status	Array of MemberStatus objects	Specifies the health status of the backend server if listener_id under status is specified. If listener_id under status is not specified, operating_status of member takes precedence.
created_at	String	Specifies the time when a backend server was added. The format is yyyy-MM-dd'T'HH:mm:ss'Z' (UTC time). This is a new field in this version, and it will not be returned for resources associated with existing dedicated load balancers and for resources associated with existing and new shared load balancers.
updated_at	String	Specifies the time when a backend server was updated. The format is yyyy-MM-dd'T'HH:mm:ss'Z' (UTC time). This is a new field in this version, and it will not be returned for resources associated with existing dedicated load balancers and for resources associated with existing and new shared load balancers.
member_type	String	Specifies the type of the backend server. Values: ip: IP as backend servers instance: ECSs used as backend servers
instance_id	String	Specifies the ID of the ECS used as the backend server. If this parameter is left blank, the backend server is not an ECS. For example, it may be an IP address.

Table 7 MemberStatus

Parameter	Type	Description
listener_id	String	Specifies the listener ID.
operating_status	String	Specifies the health status of the backend server. The value can be one of the following: ONLINE: The backend server is running normally. NO_MONITOR: No health check is configured for the backend server group to which the backend server belongs. OFFLINE: The cloud server used as the backend server is stopped or does not exist.
reason	MemberHealthCheckFailedReason object	Definition: Specifies the operating status of the backend server.
created_at	String	Definition: Specifies the creation time. The value must be a UTC time in the format of yyyy-MM-dd'T'HH:mm:ss'Z'. Range: N/A
updated_at	String	Definition: Specifies the update time. The value must be a UTC time in the format of yyyy-MM-dd'T'HH:mm:ss'Z'. Range: N/A

Table 8 MemberHealthCheckFailedReason

Parameter	Type	Description
reason_code	String	Definition: Specifies the code of the health check failures. Range: CONNECT_TIMEOUT: The connection with the backend server times out during a health check. CONNECT_REFUSED: The load balancer rejects connections with the backend server during a health check. CONNECT_FAILED: The load balancer fails to establish connections with the backend server during a health check. CONNECT_INTERRUPT: The load balancer is disconnected from the backend server during a health check. SSL_HANDSHAKE_ERROR: The SSL handshakes with the backend server fail during a health check. RECV_RESPONSE_FAILED: The load balancer fails to receive responses from the backend server during a health check. RECV_RESPONSE_TIMEOUT: The load balancer does not receive responses from the backend server within the timeout duration during a health check. SEND_REQUEST_FAILED: The load balancer fails to send a health check request to the backend server during a health check. SEND_REQUEST_TIMEOUT: The load balancer fails to send a health check request to the backend server within the timeout duration. RESPONSE_FORMAT_ERROR: The load balancer receives invalid responses from the backend server during a health check. RESPONSE_MISMATCH: The response code received from the backend server is different from the preset code.
expected_response	String	Definition: Specifies the expected HTTP status code. This parameter will take effect only when type is set to HTTP, HTTPS, or GRPC. The status code cannot be null if reason_code is RESPONSE_MISMATCH. Range: A specific status code. The status code ranges from 200 to 599. For example, the status code can be 0 or 200. A list of status codes that are separated with commas (,), for example, 200,202 or 0,1. A maximum of five status codes are supported. A status code range. Different ranges are separated with commas (,), for example, 200-204,300-399 or 0-5,10-12,20-30. A maximum of five ranges are supported.
healthcheck_response	String	Definition: Specifies the returned HTTP status code in the response. This parameter will take effect only when type is set to HTTP, HTTPS, or GRPC. The status code cannot be null if reason_code is RESPONSE_MISMATCH. Range: A specific status code. The status code ranges from 200 to 599. For example, the status code can be 0 or 200.

Example Requests

• Example 1: Adding a backend server

  POST https://{ELB_Endpoint}/v3/99a3fff0d03c428eac3678da6a7d0f24/elb/pools/36ce7086-a496-4666-9064-5ba0e6840c75/members
  
  {
    "member" : {
      "subnet_cidr_id" : "c09f620e-3492-4429-ac15-445d5dd9ca74",
      "protocol_port" : 89,
      "name" : "My member",
      "address" : "120.10.10.16"
    }
  }

• Example 2: Adding an IP as a backend server

  POST https://{ELB_Endpoint}/v3/99a3fff0d03c428eac3678da6a7d0f24/elb/pools/36ce7086-a496-4666-9064-5ba0e6840c75/members
  
  {
    "member" : {
      "protocol_port" : 89,
      "name" : "My member",
      "address" : "120.10.10.16"
    }
  }

Example Responses

Status code: 201

Normal response to POST requests.

{
  "member" : {
    "name" : "My member",
    "weight" : 1,
    "admin_state_up" : false,
    "subnet_cidr_id" : "c09f620e-3492-4429-ac15-445d5dd9ca74",
    "project_id" : "99a3fff0d03c428eac3678da6a7d0f24",
    "address" : "120.10.10.16",
    "protocol_port" : 89,
    "id" : "1923923e-fe8a-484f-bdbc-e11559b1f48f",
    "operating_status" : "NO_MONITOR",
    "status" : [ {
      "listener_id" : "427eee03-b569-4d6c-b1f1-712032f7ec2d",
      "operating_status" : "NO_MONITOR"
    } ],
    "ip_version" : "v4"
  },
  "request_id" : "f354090d-41db-41e0-89c6-7a943ec50792"
}

Status Codes

Status Code	Description
201	Normal response to POST requests.

Error Codes

See Error Codes.

Parent topic: Backend Server