doc-exports/docs/elb/api-ref/UpdatePool.html

Updating a Backend Server Group

Function

This API is used to update a backend server group.

Constraints

The backend server group can be updated only when the provisioning status of the associated load balancer is ACTIVE.

URI

PUT /v3/{project_id}/elb/pools/{pool_id}

Table 1 Path Parameters

Parameter	Mandatory	Type	Description
pool_id	Yes	String	Specifies the backend server group ID.
project_id	Yes	String	Specifies the project ID.

Request Parameters

Table 2 Request body parameters

Parameter	Mandatory	Type	Description
pool	Yes	UpdatePoolOption object	Specifies the backend server group.

Table 3 UpdatePoolOption

Parameter	Mandatory	Type	Description
admin_state_up	No	Boolean	Specifies the administrative status of the backend server group. The value can only be updated to true. This parameter is unsupported. Please do not use it.
description	No	String	Provides supplementary information about the backend server group. Minimum: 0 Maximum: 255
lb_algorithm	No	String	Specifies the load balancing algorithm used by the load balancer to route requests to backend servers. The value can be one of the following: ROUND_ROBIN: weighted round robin LEAST_CONNECTIONS: weighted least connections SOURCE_IP: source IP hash When the value is SOURCE_IP, the weights of backend servers are invalid.
name	No	String	Specifies the backend server group name. Minimum: 0 Maximum: 255
session_persistence	No	UpdatePoolSessionPersistenceOption object	Specifies whether to enable sticky sessions.
slow_start	No	UpdatePoolSlowStartOption object	Specifies whether to enable slow start. After you enable slow start, new backend servers added to the backend server group are warmed up, and the number of requests they can receive increases linearly during the configured slow start duration. This parameter can be used when the protocol of the backend server group is HTTP or HTTPS. An error will be returned if the protocol is not HTTP or HTTPS. This parameter is unsupported. Please do not use it.

Table 4 UpdatePoolSessionPersistenceOption

Parameter	Mandatory	Type	Description
cookie_name	No	String	Specifies the cookie name. This parameter will take effect only when type is set to APP_COOKIE. Otherwise, an error will be returned. The value can contain only letters, digits, hyphens (-), underscores (_), and periods (.). Minimum: 0 Maximum: 1024
type	Yes	String	Specifies the sticky session type. The value can be SOURCE_IP, HTTP_COOKIE, or APP_COOKIE. If the protocol of the backend server group is TCP or UDP, only SOURCE_IP takes effect. If the value is not SOURCE_IP, sticky sessions will not take effect. For dedicated load balancers, if the protocol of the backend server group is HTTP or HTTPS, the value can only be HTTP_COOKIE. For shared load balancers, if the protocol of the backend server group is HTTP or HTTPS, the value can be HTTP_COOKIE or APP_COOKIE. If the value is not HTTP_COOKIE or APP_COOKIE, sticky sessions will not take effect.
persistence_timeout	No	Integer	Specifies the stickiness duration, in minutes. If the protocol of the backend server group is TCP or UDP, the value ranges from 1 to 60, and the default value is 1. If the protocol of the backend server group is HTTP or HTTPS, the value ranges from 1 to 1440, and the default value is 1440.

Table 5 UpdatePoolSlowStartOption

Parameter	Mandatory	Type	Description
enable	Yes	Boolean	Specifies whether slow start is enabled. true indicates that slow start is enabled, and false indicates slow start is disabled. Default: false
duration	Yes	Integer	Specifies the slow start duration, in seconds. The value ranges from 30 to 1200, and the default value is 30. Minimum: 30 Maximum: 1200 Default: 30

Response Parameters

Status code: 200

Table 6 Response body parameters

Parameter	Type	Description
request_id	String	Specifies the request ID. The value is automatically generated.
pool	Pool object	Specifies the backend server group.

Table 7 Pool

Parameter	Type	Description
admin_state_up	Boolean	Specifies the administrative status of the backend server group. The value can only be updated to true. This parameter is unsupported. Please do not use it. Default: true
description	String	Provides supplementary information about the backend server group.
healthmonitor_id	String	Specifies the ID of the health check configured for the backend server group.
id	String	Specifies the backend server group ID.
lb_algorithm	String	Specifies the load balancing algorithm used by the load balancer to route requests to backend servers in the backend server group. The value can be ROUND_ROBIN (weighted round robin), LEAST_CONNECTIONS (weighted least connections), or SOURCE_IP (source IP hash). When the value is SOURCE_IP, the weight parameter is invalid.
listeners	Array of ListenerRef objects	Lists the listeners associated with the backend server group.
loadbalancers	Array of LoadBalancerRef objects	Lists the IDs of load balancers associated with the backend server group. If only listener_id is specified during the creation of the backend server group, the ID of the loadbalancers parameter in the response is the ID of the load balancer to which the listener is added.
members	Array of MemberRef objects	Lists the backend servers in the backend server group.
name	String	Specifies the backend server group name.
project_id	String	Specifies the project ID.
protocol	String	Specifies the protocol used by the backend server group to receive requests. The protocol can be TCP, UDP, or HTTP. For UDP listeners, the protocol of the backend server group must be UDP. For TCP listeners, the protocol of the backend server group must be TCP. For HTTP or HTTPS listeners, the protocol of the backend server group must be HTTP.
session_persistence	SessionPersistence object	Specifies the sticky session.
ip_version	String	Specifies the IP version supported by the backend server group. Shared load balancers: The default value is v4. Dedicated load balancers: The value can be dualstack, v4, or v6. When the protocol of the backend server group is TCP or UDP, ip_version is set to dualstack, indicating that both IPv4 and IPv6 are supported. When the protocol of the backend server group is HTTP, ip_version is set to v4. Default: dualstack
slow_start	SlowStart object	Specifies whether to enable slow start. After you enable slow start, new backend servers added to the backend server group are warmed up, and the number of requests they can receive increases linearly during the configured slow start duration. This parameter can be used when the protocol of the backend server group is HTTP or HTTPS. An error will be returned if the protocol is not HTTP or HTTPS. This parameter is unsupported. Please do not use it.

Table 8 ListenerRef

Parameter	Type	Description
id	String	Specifies the listener ID.

Table 9 LoadBalancerRef

Parameter	Type	Description
id	String	Specifies the load balancer ID.

Table 10 MemberRef

Parameter	Type	Description
id	String	Specifies the backend server ID.

Table 11 SessionPersistence

Parameter	Type	Description
cookie_name	String	Specifies the cookie name. This parameter will take effect only when type is set to APP_COOKIE. Otherwise, an error will be returned. The value can contain only letters, digits, hyphens (-), underscores (_), and periods (.). Minimum: 0 Maximum: 1024
type	String	Specifies the sticky session type. The value can be SOURCE_IP, HTTP_COOKIE, or APP_COOKIE. If the protocol of the backend server group is TCP or UDP, only SOURCE_IP takes effect. If the value is not SOURCE_IP, sticky sessions will not take effect. For dedicated load balancers, if the protocol of the backend server group is HTTP or HTTPS, the value can only be HTTP_COOKIE. For shared load balancers, if the protocol of the backend server group is HTTP or HTTPS, the value can be HTTP_COOKIE or APP_COOKIE. If the value is not HTTP_COOKIE or APP_COOKIE, sticky sessions will not take effect.
persistence_timeout	Integer	Specifies the stickiness duration, in minutes. If the protocol of the backend server group is TCP or UDP, the value ranges from 1 to 60, and the default value is 1. If the protocol of the backend server group is HTTP or HTTPS, the value ranges from 1 to 1440, and the default value is 1440.

Table 12 SlowStart

Parameter	Type	Description
enable	Boolean	Specifies whether to enable slow start. true indicates that this function is enabled, and false indicates this function is disabled. Default: false
duration	Integer	Specifies the slow start duration, in seconds. The value ranges from 30 to 1200, and the default value is 30. Minimum: 30 Maximum: 1200 Default: 30

Example Requests

PUT

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

{
  "pool" : {
    "name" : "My pool.",
    "description" : "My pool update",
    "lb_algorithm" : "LEAST_CONNECTIONS"
  }
}

Example Responses

Status code: 200

Successful request.

{
  "pool" : {
    "lb_algorithm" : "LEAST_CONNECTIONS",
    "protocol" : "TCP",
    "description" : "My pool update",
    "admin_state_up" : true,
    "loadbalancers" : [ {
      "id" : "098b2f68-af1c-41a9-8efd-69958722af62"
    } ],
    "project_id" : "99a3fff0d03c428eac3678da6a7d0f24",
    "session_persistence" : null,
    "healthmonitor_id" : null,
    "listeners" : [ {
      "id" : "0b11747a-b139-492f-9692-2df0b1c87193"
    }, {
      "id" : "61942790-2367-482a-8b0e-93840ea2a1c6"
    }, {
      "id" : "fd8f954c-f0f8-4d39-bb1d-41637cd6b1be"
    } ],
    "members" : [ ],
    "id" : "36ce7086-a496-4666-9064-5ba0e6840c75",
    "name" : "My pool.",
    "ip_version" : "dualstack"
  },
  "request_id" : "8f40128b-c72b-4b64-986a-f7e2c633d75f"
}

Status Codes

Status Code	Description
200	Successful request.

Error Codes

See Error Codes.

Parent topic: Backend Server Group