Querying Backend Servers

Updated on 2025-02-24 GMT+08:00

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Function

This API is used to query all backend servers.

Constraints

This API has the following constraints:

Parameters marker, limit, and page_reverse are used for pagination query.
Parameters marker and page_reverse take effect only when they are used together with parameter limit.

Calling Method

For details, see Calling APIs.

URI

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

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

**Table 2** Query Parameters
Parameter	Mandatory	Type	Description
marker	No	String	Specifies the ID of the last record on the previous page. Note: This parameter must be used together with limit. If this parameter is not specified, the first page will be queried. This parameter cannot be left blank or set to an invalid ID.
limit	No	Integer	Specifies the number of records on each page. Value range: 0–2000 Default value: 2000
page_reverse	No	Boolean	Specifies whether to use reverse query. Value options: true: Query the previous page. false (default): Query the next page. Note: This parameter must be used together with limit. If page_reverse is set to true and you want to query the previous page, set the value of marker to the value of previous_marker.
name	No	Array of strings	Specifies the backend server name. Multiple names can be queried in the format of name=xxx&name=xxx.
weight	No	Array of integers	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. 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. Multiple weights can be queried in the format of weight=xxx&weight=xxx.
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 ECSs exist. If ECSs exist, the value is true. Otherwise, the value is false.
subnet_cidr_id	No	Array of strings	Specifies the ID of the IPv4 or IPv6 subnet where the backend server resides. Multiple IDs can be queried in the format of subnet_cidr_id=xxx&subnet_cidr_id=xxx.
address	No	Array of strings	Specifies the IP address bound to the backend server. Multiple IP addresses can be queried in the format of address=xxx&address=xxx.
protocol_port	No	Array of integers	Specifies the port used by the backend server to receive requests. Multiple ports can be queried in the format of protocol_port=xxx&protocol_port=xxx.
id	No	Array of strings	Specifies the backend server ID. Multiple IDs can be queried in the format of id=xxx&id=xxx.
operating_status	No	Array of strings	Specifies the health status of the backend server. Value options: 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. Multiple operating statuses can be queried in the format of operating_status=xxx&operating_status=xxx.
enterprise_project_id	No	Array of strings	Specifies the ID of the enterprise project. If enterprise_project_id is not specified, resources in all enterprise projects are queried by default. Fine-grained authorization is performed. The elb:members:list permission must be assigned to the user group. If enterprise_project_id is specified, the value can be a specific enterprise project ID or all_granted_eps. If the value is a specific enterprise project ID, only resources in the enterprise project are queried. If the value is all_granted_eps, resources in the enterprise projects with the elb:members:list permission are queried. Multiple values can be queried in the format of enterprise_project_id=xxx&enterprise_project_id=xxx.
ip_version	No	Array of strings	Specifies the IP version supported by the backend server. The value can be v4 (IPv4) or v6 (IPv6).
member_type	No	Array of strings	Specifies the type of the backend server. Value options: ip: IP as backend servers instance: ECSs used as backend servers Multiple values can be queried in the format of member_type=xxx&member_type=xxx.
instance_id	No	Array of strings	Specifies the ID of the instance associated with the backend server. If this parameter is left blank, the backend server is not an ECS. It may be an IP address. Multiple instance IDs can be queried in the format of instance_id=xxx&instance_id=xxx.

Request Parameters

**Table 3** Request header parameters
Parameter	Mandatory	Type	Description
X-Auth-Token	Yes	String	Specifies the token used for IAM authentication.

Response Parameters

Status code: 200

**Table 4** Response body parameters
Parameter	Type	Description
request_id	String	Specifies the request ID. Note: The value is automatically generated.
page_info	PageInfo object	Shows pagination information.
members	Array of Member objects	Specifies the backend servers.

**Table 5** PageInfo
Parameter	Type	Description
previous_marker	String	Specifies the ID of the first record in the pagination query result. When page_reverse is set to true, this parameter is used together to query resources on the previous page.
next_marker	String	Specifies the ID of the last record in the pagination query result.
current_count	Integer	Specifies the number of records.

**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 been 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.
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 ECSs exist. If ECSs 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. neutron_subnet_id defines IPv4 subnets, and neutron_network_id defines IPv6 subnets. You can query parameters neutron_subnet_id and neutron_network_id in the response by calling the API GET https://{VPC_Endpoint}/v1/{project_id}/subnets to get the IPv4 subnet ID and IPv6 subnet ID respectively. Note: The IPv4 or IPv6 subnet must be in the same VPC as the subnet of the load balancer. If ip_target_enable is set to true, this parameter can be left blank. In this case, IP as backend servers must use private IPv4 addresses, and the protocol of the backend server group must be TCP, UDP, TLS, HTTP, HTTPS, QUIC, or GRPC. If ip_target_enable is set to false, this parameter must be specified.
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.
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 or QUIC_CID, this parameter will not take effect.
address	String	Specifies the private IP address bound to the backend server. Note: 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.
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 if listener_id under status is not specified. Value options: 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.
reason	MemberHealthCheckFailedReason object	Specifies why health check fails.
created_at	String	Specifies the time when the 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 the 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. Value options: ip: IP as backend servers instance: ECSs used as backend servers
instance_id	String	Specifies the ID of the instance associated with the backend server. If this parameter is left blank, the backend server is not a real device. 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. Value options: 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	Specifies why health check fails.

**Table 8** MemberHealthCheckFailedReason
Parameter	Type	Description
reason_code	String	Specifies the code of the health check failures. Value options: 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	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. Value ranges: A specific status code. If type is set to GRPC, the status code ranges from 0 to 99. If type is set to other values, 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	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. Value range: A specific status code. If type is set to GRPC, the status code ranges from 0 to 99. If type is set to other values, the status code ranges from 200 to 599. For example, the status code can be 0 or 200.

Example Requests

Querying backend servers in a given backend server group

GET https://{ELB_Endpoint}/v3/99a3fff0d03c428eac3678da6a7d0f24/elb/pools/36ce7086-a496-4666-9064-5ba0e6840c75/members

Example Responses

Status code: 200

Successful request.

{
  "members" : [ {
    "name" : "quark-neutron",
    "weight" : 100,
    "admin_state_up" : false,
    "subnet_cidr_id" : "c09f620e-3492-4429-ac15-445d5dd9ca74",
    "project_id" : "99a3fff0d03c428eac3678da6a7d0f24",
    "address" : "120.10.10.2",
    "protocol_port" : 2100,
    "id" : "0aa23a52-1ac2-4a2d-8dfa-1e11cb26079d",
    "operating_status" : "NO_MONITOR",
    "ip_version" : "v4"
  }, {
    "name" : "quark-neutron",
    "weight" : 100,
    "admin_state_up" : false,
    "subnet_cidr_id" : "c09f620e-3492-4429-ac15-445d5dd9ca74",
    "project_id" : "99a3fff0d03c428eac3678da6a7d0f24",
    "address" : "120.10.10.2",
    "protocol_port" : 2101,
    "id" : "315b928b-39e4-4d5f-8e48-39e9108c1035",
    "operating_status" : "NO_MONITOR",
    "ip_version" : "v4"
  }, {
    "name" : "quark-neutron",
    "weight" : 100,
    "admin_state_up" : false,
    "subnet_cidr_id" : "27e4ab69-a5ed-46c6-921a-5212be19ce87",
    "project_id" : "99a3fff0d03c428eac3678da6a7d0f24",
    "address" : "2001:db8:a583:6a::4",
    "protocol_port" : 2101,
    "id" : "53976f72-d2aa-47f5-baf4-4906ed6b42d6",
    "operating_status" : "NO_MONITOR",
    "ip_version" : "v6"
  } ],
  "page_info" : {
    "previous_marker" : "0aa23a52-1ac2-4a2d-8dfa-1e11cb26079d",
    "current_count" : 3
  },
  "request_id" : "87e29592-7ab8-401a-9bf4-66cf6747eab9"
}