Adding a Backend Server

Function

This API is used to add a backend server to a specific backend server group. After a backend server group is added to a listener, traffic is distributed to backend servers in this server group using the specified load balancing algorithm.

Constraints

Two backend servers in a backend server group cannot have the same private IP address or port number.

The subnet specified during server creation must be in the same VPC as the subnet from which the private IP address of the load balancer is assigned.

You can call this API for a maximum of 200 times per minute globally.

URI

POST /v2/{project_id}/elb/pools/{pool_id}/members

**Table 1** Parameter description
Parameter	Mandatory	Type	Description
project_id	Yes	String	Specifies the project ID.
pool_id	Yes	String	Specifies the ID of the backend server group.

Request

**Table 2** Parameter description
Parameter	Mandatory	Type	Description
member	Yes	Member object	Specifies the backend server. For details, see Table 3.

**Table 3** **member** parameter description
Parameter	Mandatory	Type	Description
tenant_id	No	String	Specifies the ID of the project where the backend server is used. The value must be the same as the value of project_id in the token. The value contains a maximum of 255 characters.
name	No	String	Specifies the backend server name. The value is an empty character string by default. The value contains a maximum of 255 characters.
address	Yes	String	Specifies the private IP address of the backend server. This IP address must be in the subnet specified by subnet_id. This parameter can be set only to the IP address of the primary NIC, for example, 192.168.3.11. The value contains a maximum of 64 characters.
protocol_port	Yes	Integer	Specifies the port used by the backend server. The port number ranges from 1 to 65535.
subnet_id	Yes	String	Specifies the ID of the subnet where the backend server resides. The private IP address of the backend server is in this subnet. Only IPv4 subnets are supported.
admin_state_up	No	Boolean	Specifies the administrative status of the backend server. This parameter is reserved, and the default value is true.
weight	No	Integer	Specifies the backend server weight. The value ranges from 0 to 100. If the value is 0, the backend server will not accept new requests. The default value is 1.

Response

**Table 4** Parameter description
Parameter	Type	Description
member	Member object	Specifies the backend server. For details, see Table 5.

**Table 5** **member** parameter description
Parameter	Type	Description
id	String	Specifies the backend server ID. NOTE: The value of this parameter is not the ID of server. It is the ID automatically generated for the backend server associated with the load balancer.
tenant_id	String	Specifies the ID of the project where the backend server is used. The value contains a maximum of 255 characters.
project_id	String	Specifies the ID of the project to which the backend server belongs. This parameter has the same meaning as tenant_id.
name	String	Specifies the backend server name. The value contains a maximum of 255 characters.
address	String	Specifies the private IP address of the backend server. This IP address must be in the subnet specified by subnet_id. This parameter can be set only to the IP address of the primary NIC, for example, 192.168.3.11. The value contains a maximum of 64 characters.
protocol_port	Integer	Specifies the port used by the backend server. The port number ranges from 1 to 65535.
subnet_id	String	Specifies the ID of the subnet where the backend server resides. The private IP address of the backend server is in this subnet. IPv6 subnets are not supported.
admin_state_up	Boolean	Specifies the administrative status of the backend server. This parameter is reserved. The value can be true or false. true: Enabled false: Disabled
weight	Integer	Specifies the backend server weight. The value ranges from 0 to 100. If the value is 0, the backend server will not accept new requests. The default value is 1.
operating_status	String	Specifies the health check result 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 that the backend server belongs to. OFFLINE: The cloud server used as the backend server is stopped or does not exist.

Example Request

Adding a backend server
Obtain the values of subnet_id and ip_address by querying the subnet ID and IP address of the server associated with the load balancer.
Alternatively, query the subnet ID and IP address using the server ID. device_id in the request indicates the server ID. Obtain the values of subnet_id and ip_address of the primary NIC (the port for which primary_interface is true) in the response body.
```
POST https://{Endpoint}/v2/145483a5107745e9b3d80f956713e6a3/elb/pools/5a9a3e9e-d1aa-448e-af37-a70171f2a332/members

{
    "member": {
        "subnet_id": "33d8b01a-bbe6-41f4-bc45-78a1d284d503",
        "protocol_port": 88,
        "name": "member-jy-tt-1",
        "address": "192.168.44.11"
    }
}
```

Example Response

Example response

{
    "member": {
        "name": "member-jy-tt-1", 
        "weight": 1, 
        "admin_state_up": true, 
        "subnet_id": "33d8b01a-bbe6-41f4-bc45-78a1d284d503", 
        "tenant_id": "145483a5107745e9b3d80f956713e6a3", 
        "project_id": "145483a5107745e9b3d80f956713e6a3", 
        "address": "192.168.44.11", 
        "protocol_port": 88, 
        "operating_status": "ONLINE", 
        "id": "c0042496-e220-44f6-914b-e6ca33bab503"
    }
}