Adding a Backend Server

Updated on 2024-04-09 GMT+08:00

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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.
If type of the backend server is set to instance, address must be a private IP address that is not used by any load balancer.

Calling Method

For details, see Calling APIs.

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. Note: The name is not an ECS name. If this parameter is not specified, an empty value will be returned. Minimum: 0 Maximum: 255
project_id	No	String	Specifies the project ID. Minimum: 1 Maximum: 32
protocol_port	No	Integer	Specifies the port used by the backend server to receive requests. NOTE: This parameter can be left blank because it does not take effect if any_port_enable is set to true for a backend server group. Minimum: 1 Maximum: 65535
subnet_cidr_id	No	String	Specifies the ID of the subnet where the backend server resides. It can be an ID of an IPv4 or IPv6 subnet. If you use an IPv4 subnet, you can query parameter neutron_subnet_id in the response by calling the API (GET https://{VPC_Endpoint}/v1/{project_id}/subnets) to obtain the ID of the IPv4 subnet. If you use an IPv6 subnet, you can query parameter neutron_network_id in the response by calling the API (GET https://{VPC_Endpoint}/v1/{project_id}/subnets) to obtain the ID of the IPv6 subnet. Note: The IPv4 or IPv6 subnet must be in the same VPC as the subnet of the load balancer. If IP as a Backend has been enabled for the load balancer, you do not need to specify this parameter. 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.

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.
name	String	Specifies the backend server name. Note: The name is not an ECS name.
project_id	String	Specifies the project ID of the backend server.
pool_id	String	Specifies the ID of the backend server group to which the backend server belongs. This parameter is unsupported. Please do not use it.
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 subnet where the backend server resides. It can be an ID of an IPv4 or IPv6 subnet. If you use an IPv4 subnet, you can query parameter neutron_subnet_id in the response by calling the API (GET https://{VPC_Endpoint}/v1/{project_id}/subnets) to obtain the ID of the IPv4 subnet. If you use an IPv6 subnet, you can query parameter neutron_network_id in the response by calling the API (GET https://{VPC_Endpoint}/v1/{project_id}/subnets) to obtain the ID of the IPv6 subnet. Note: The IPv4 or IPv6 subnet must be in the same VPC as the subnet of the load balancer. If IP as a Backend has been enabled for the load balancer, you do not need to specify this parameter. 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.
protocol_port	Integer	Specifies the port used by the backend server to receive requests. NOTE: This parameter can be left blank because it does not take effect if any_port_enable is set to true for a backend server group. 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.
device_owner	String	Specifies whether the backend server is associated with an ECS. If this parameter is left blank, the backend server is not associated with an ECS. If the value is compute:{az_name}, the backend server is associated with an ECS. {az_name} indicates the AZ where the ECS resides. This parameter is unsupported. Please do not use it.
device_id	String	Specifies the ID of the ECS with which the backend server is associated. If this parameter is left blank, the backend server is not associated with an ECS. This parameter is unsupported. Please do not use it.
operating_status	String	Specifies the health status of the backend server if listener_id under status is not specified. 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 is specified.
loadbalancer_id	String	Specifies the ID of the load balancer with which the backend server is associated. This parameter is unsupported. Please do not use it.
loadbalancers	Array of ResourceID objects	Specifies the IDs of the load balancers associated with the backend server. This parameter is unsupported. Please do not use it.
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.

**Table 8** ResourceID
Parameter	Type	Description
id	String	Specifies the resource ID.

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 a server of IP as a Backend

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"
}