Querying Backend Server Groups

Function

This API is used to query the backend server groups and display them in a list. Filter query and pagination query are supported. Unless otherwise specified, exact match is applied.

URI

GET /v2/{project_id}/elb/pools

**Table 1** Parameter description
Parameter	Mandatory	Type	Description
project_id	Yes	String	Specifies the project ID.

Request

**Table 2** Parameter description
Parameter	Mandatory	Type	Description
marker	No	String	Specifies the ID of the backend server group from which pagination query starts, that is, the ID of the last backend server group on the previous page. If this parameter is not specified, the first page will be queried. This parameter must be used together with limit.
limit	No	Integer	Specifies the number of backend server groups on each page. If this parameter is not set, all backend server groups are queried by default.
page_reverse	No	Boolean	Specifies the page direction. The value can be true or false, and the default value is false. The last page in the list requested with page_reverse set to false will not contain the "next" link, and the last page in the list requested with page_reverse set to true will not contain the "previous" link. This parameter must be used together with limit.
id	No	String	Specifies the ID of the backend server group.
name	No	String	Specifies the name of the backend server group. The value contains a maximum of 255 characters.
description	No	String	Provides supplementary information about the backend server group. The value contains a maximum of 255 characters.
healthmonitor_id	No	String	Specifies the ID of the health check configured for the backend server group.
loadbalancer_id	No	String	Specifies the ID of the load balancer associated with the backend server group.
protocol	No	String	Specifies the protocol that the backend server group uses to receive requests. TCP, UDP, and HTTP are supported.
lb_algorithm	No	String	Specifies the load balancing algorithm of the backend server group. The value range varies depending on the protocol of the backend server group: ROUND_ROBIN: indicates the weighted round robin algorithm. LEAST_CONNECTIONS: indicates the weighted least connections algorithm. SOURCE_IP: indicates the source IP hash algorithm. When the value is SOURCE_IP, the weights of backend servers in the server group are invalid. For details about parameter weight, see Response.
member_address	No	String	Lists the IDs of backend servers in the backend server group.
member_device_id	No	String	Specifies the ID of the ECS corresponding to the backend server in the backend server group.
enterprise_project_id	No	String	Specifies the enterprise project ID. Enterprise projects are used for fine-grained authentication. If loadbalancer_id is transmitted, the ID of the enterprise project to which the load balancer is assigned is used for authentication. If loadbalancer_id is not transmitted but healthmonitor_id is transmitted, the ID of the enterprise project to which the health check is assigned is used for authentication.

Response

**Table 3** Parameter description
Parameter	Type	Description
pools	Array	Specifies the backend server group. For details, see Table 4.

**Table 4** **pool** parameter description
Parameter	Type	Description
id	String	Specifies the ID of the backend server group.
tenant_id	String	Specifies the ID of the project where the backend server group is used. The value contains a maximum of 255 characters.
name	String	Specifies the name of the backend server group. The value contains a maximum of 255 characters.
description	String	Provides supplementary information about the backend server group. The value contains a maximum of 255 characters.
protocol	String	Specifies the protocol that the backend server group uses to receive requests. TCP, UDP, and HTTP are supported. When a backend server group is associated with a listener, the relationships between the protocol used by the listener and the protocol of the backend server group are as follows: When the protocol used by the listener is UDP, the protocol of the backend server group must be UDP. When the protocol used by the listener is TCP, the protocol of the backend server group must be TCP. When the protocol used by the listener is HTTP or TERMINATED_HTTPS, the protocol of the backend server group must be HTTP.
lb_algorithm	String	Specifies the load balancing algorithm of the backend server group. The value range varies depending on the protocol of the backend server group: ROUND_ROBIN: indicates the weighted round robin algorithm. LEAST_CONNECTIONS: indicates the weighted least connections algorithm. SOURCE_IP: indicates the source IP hash algorithm. When the value is SOURCE_IP, the weights of backend servers in the server group are invalid.
members	Array	Lists the IDs of backend servers in the backend server group. For details, see Table 7.
healthmonitor_id	String	Specifies the ID of the health check configured for the backend server group.
admin_state_up	Boolean	Specifies the administrative status of the backend server group. This parameter is reserved. The default value is true.
listeners	Array	Lists the IDs of listeners associated with the backend server group. For details, see Table 8.
loadbalancers	Array	Lists the IDs of load balancers associated with the backend server group. For details, see Table 9.
session_persistence	Object	Specifies whether to enable the sticky session feature. For details, see Table 10. Once the sticky session feature is enabled, requests from the same client are sent to the same backend server within the specified period. When this feature is disabled, the parameter value is null.

**Table 5** **members** parameter description
Parameter	Type	Description
id	String	Specifies the ID of the associated backend server.

**Table 6** **listeners** parameter description
Parameter	Type	Description
id	String	Specifies the ID of the associated backend server group.

**Table 7** **loadbalancers** parameter description
Parameter	Type	Description
id	String	Specifies the ID of the associated load balancer.

**Table 8** **session_persistence** parameter description
Parameter	Mandatory	Type	Description
type	Yes	String	Specifies the sticky session type. The value range varies depending on the protocol of the backend server group: SOURCE_IP: Requests are distributed based on the client's IP address. Requests from the same IP address are sent to the same backend server. HTTP_COOKIE: When the client sends a request for the first time, the load balancer automatically generates a cookie and inserts the cookie into the response message. Subsequent requests are sent to the backend server that processes the first request. APP_COOKIE: When the client sends a request for the first time, the backend server that receives the request generates a cookie and inserts the cookie into the response message. Subsequent requests are sent to this backend server. When the protocol of the backend server group is TCP, only SOURCE_IP takes effect. When the protocol of the backend server group is HTTP, only HTTP_COOKIE or APP_COOKIE takes effect.
cookie_name	No	String	Specifies the cookie name. This parameter is mandatory when the sticky session type is APP_COOKIE.
persistence_timeout	No	Integer	Specifies the sticky session timeout duration in minutes. This parameter is invalid when type is set to APP_COOKIE. The value range varies depending on the protocol of the backend server group: When the protocol of the backend server group is TCP or UDP, the value ranges from 1 to 60. When the protocol of the backend server group is HTTP, the value ranges from 1 to 1440.

Example Request

Example request 1: Querying all backend server groups

GET https://{Endpoint}/v2/1867112d054b427e808cc6096d8193a1/elb/pools

Example request 2: Querying backend server groups whose load balancing algorithm is SOURCE_IP
```
GET https://{Endpoint}/v2/1867112d054b427e808cc6096d8193a1/elb/pools?lb_algorithm=SOURCE_IP
```

Example Response

Example response 1

{
    "pools": [
        {
            "lb_algorithm": "SOURCE_IP",
            "protocol": "TCP",
            "description": "",
            "admin_state_up": true,
            "loadbalancers": [
                {
                    "id": "07d28d4a-4899-40a3-a939-5d09d69019e1"
                }
            ],
            "tenant_id": "1867112d054b427e808cc6096d8193a1",
            "session_persistence": null,
            "healthmonitor_id": null,
            "listeners": [
                {
                    "id": "1b421c2d-7e78-4a78-9ee4-c8ccba41f15b"
                }
            ],
            "members": [
                {
                    "id": "88f9c079-29cb-435a-b98f-0c5c0b90c2bd"
                },
                {
                    "id": "2f4c9644-d5d2-4cf8-a3c0-944239a4f58c"
                }
            ],
            "id": "3a9f50bb-f041-4eac-a117-82472d8a0007",
            "name": "my-pool"
        }
    ]
}

Example response 2

{
    "pools": [
        {
            "lb_algorithm": "SOURCE_IP",
            "protocol": "TCP",
            "description": "",
            "admin_state_up": true,
            "loadbalancers": [
                {
                    "id": "07d28d4a-4899-40a3-a939-5d09d69019e1"
                }
            ],
            "tenant_id": "1867112d054b427e808cc6096d8193a1",
 
            "session_persistence": null,
            "healthmonitor_id": null,
            "listeners": [
                {
                    "id": "1b421c2d-7e78-4a78-9ee4-c8ccba41f15b"
                }
            ],
            "members": [
                {
                    "id": "88f9c079-29cb-435a-b98f-0c5c0b90c2bd"
                },
                {
                    "id": "2f4c9644-d5d2-4cf8-a3c0-944239a4f58c"
                }
            ],
            "id": "3a9f50bb-f041-4eac-a117-82472d8a0007",
            "name": "my-pool"
        }
    ]
}