Updated on 2023-12-18 GMT+08:00

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"
        }
    }

Status Code

For details, see Status Codes.