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.

Calling Method

For details, see Calling APIs.

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

**Table 3** Request body parameters
Parameter	Mandatory	Type	Description
pool	Yes	UpdatePoolOption object	Specifies the backend server group.

**Table 4** 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.
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 in the associated backend server group. The value can be one of the following: ROUND_ROBIN: weighted round robin LEAST_CONNECTIONS: weighted least connections SOURCE_IP: source IP hash QUIC_CID: connection ID 2_TUPLE_HASH: 2-tuple hash that is only available for IP backend server groups 3_TUPLE_HASH: 3-tuple hash that is only available for IP backend server groups 5_TUPLE_HASH: 5-tuple hash that is only available for IP backend server groups Note: If the value is SOURCE_IP, the weight parameter will not take effect for backend servers. QUIC_CID is supported only when the protocol of the backend server group is QUIC. QUIC_CID is not supported.
name	No	String	Specifies the backend server group name. Minimum: 0 Maximum: 255
session_persistence	No	UpdatePoolSessionPersistenceOption object	Specifies the sticky session.
slow_start	No	UpdatePoolSlowStartOption object	Specifies slow start details. 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 not supported by gateway load balancers. Please do not use it.
member_deletion_protection_enable	No	Boolean	Specifies whether to enable removal protection for the load balancer. true: Enable removal protection. false: Disable removal protection. NOTE: Disable removal protection for all your resources before deleting your account. This parameter is unsupported. Please do not use it.
vpc_id	No	String	Specifies the ID of the VPC where the backend server group works. vpc_id must be specified for IP backend server groups. The value must be the same as that defined by vpc_id for the load balancer. This parameter can be updated only when vpc_id is left blank. Minimum: 0 Maximum: 36
type	No	String	Specifies the type of the backend server group. Values: instance: Any type of backend servers can be added. vpc_id is mandatory. ip: Only IP as backend servers can be added. vpc_id cannot be specified. type cannot be set to ip if the backend server group protocol is IP. "": Any type of backend servers can be added. Note: This parameter can be updated only when type is left blank.
pool_health	No	PoolHealth object	Specifies the configurations of the pool health feature.

**Table 5** UpdatePoolSessionPersistenceOption
Parameter	Mandatory	Type	Description
cookie_name	No	String	Specifies the cookie name. The name can contain a maximum of 255 characters, including letters, digits, underscores (_), hyphens (-), and periods (.). Note: This parameter will take effect only when type is set to APP_COOKIE. Otherwise, an error will be returned. This parameter is not supported by gateway load balancers. Please do not use it. This parameter is unsupported. Please do not use it.
type	No	String	Specifies the sticky session type. The value can be SOURCE_IP, HTTP_COOKIE, or APP_COOKIE. Note: If the protocol of the backend server group is TCP or UDP, only SOURCE_IP takes effect. If the protocol of the backend server group is HTTP or HTTPS, the value can only be HTTP_COOKIE. QUIC protocol is not supported.
persistence_timeout	No	Integer	Specifies the stickiness duration, in minutes. This parameter will not take effect when type is set to APP_COOKIE. If the protocol of the backend server group is TCP, UDP, or QUIC, 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. QUIC protocol is not supported.

**Table 6** UpdatePoolSlowStartOption
Parameter	Mandatory	Type	Description
enable	No	Boolean	Specifies whether to enable slow start. true: Enable slow start. false: Disable slow start.
duration	No	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

**Table 7** PoolHealth
Parameter	Mandatory	Type	Description
minimum_healthy_member_count	No	Integer	If the number of healthy backend servers is less than the value specified for this parameter, the backend server group is considered as unhealthy. The value can be 0 (disabled) or 1 (enabled).

Response Parameters

Status code: 200

**Table 8** 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 9** Pool
Parameter	Type	Description
admin_state_up	Boolean	Specifies the administrative status of the backend server group.
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 associated backend server group. The value can be one of the following: ROUND_ROBIN: weighted round robin LEAST_CONNECTIONS: weighted least connections SOURCE_IP: source IP hash QUIC_CID: connection ID 2_TUPLE_HASH: 2-tuple hash that is only available for IP backend server groups 3_TUPLE_HASH: 3-tuple hash that is only available for IP backend server groups 4_TUPLE_HASH: 4-tuple hash that is only available for IP backend server groups Note: If the value is SOURCE_IP, the weight parameter will not take effect for backend servers. QUIC_CID is supported only when the protocol of the backend server group is QUIC. QUIC_CID is not supported.
listeners	Array of ListenerRef objects	Specifies the IDs of the listeners with which the backend server group is associated.
loadbalancers	Array of LoadBalancerRef objects	Specifies the IDs of the load balancers with which the backend server group is associated.
members	Array of MemberRef objects	Specifies the IDs of 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 value can be TCP, UDP, IP, TLS, HTTP, HTTPS, gRPC, or QUIC. Note: If the listener's protocol is UDP, the protocol of the backend server group must be UDPor QUIC. If the listener's protocol is TCP, the protocol of the backend server group must be TCP. If the listener's protocol is IP, the protocol of the backend server group must be IP. If the listener's protocol is HTTP, the protocol of the backend server group must be HTTP. If the listener's protocol is HTTPS, the protocol of the backend server group can be HTTP, HTTPS, or gRPC. If the listener's protocol is TERMINATED_HTTPS, the protocol of the backend server group must be HTTP. If the listener's protocol is QUIC, the protocol of the backend server group can be HTTP, HTTPS, or gRPC. If the listener's protocol is TLS, the protocol of the backend server group can be TLS or TCP. If protocol of the backend server group is TCP, the ip_version must be set to v4. Note: If protocol of the backend server group is QUIC, session_persistence must be set to true, with type set to SOURCE_IP. If protocol of the backend server group is gRPC, http2_enable of the listener must be set to true. QUIC is not supported.
session_persistence	SessionPersistence object	Specifies the sticky session.
ip_version	String	Specifies the IP address version supported by the backend server group.
slow_start	SlowStart object	Specifies slow start details. 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.
member_deletion_protection_enable	Boolean	Specifies whether to enable removal protection. true: Enable removal protection. false: Disable removal protection. NOTE: Disable removal protection for all your resources before deleting your account. This parameter is unsupported. Please do not use it.
created_at	String	Specifies the time when a backend server group was created. The format is yyyy-MM-dd'T'HH:mm:ss'Z' (UTC time).
updated_at	String	Specifies the time when when a backend server group was updated. The format is yyyy-MM-dd'T'HH:mm:ss'Z' (UTC time).
vpc_id	String	Specifies the ID of the VPC where the backend server group works.
type	String	Specifies the type of the backend server group. Values: instance: Any type of backend servers can be added. vpc_id is mandatory. ip: Only IP as backend servers can be added. vpc_id cannot be specified. "": Any type of backend servers can be added.
enterprise_project_id	String	Specifies the enterprise project ID of the IP address group.

**Table 10** ListenerRef
Parameter	Type	Description
id	String	Specifies the listener ID.

**Table 11** LoadBalancerRef
Parameter	Type	Description
id	String	Specifies the load balancer ID.

**Table 12** MemberRef
Parameter	Type	Description
id	String	Specifies the backend server ID.

**Table 13** SessionPersistence
Parameter	Type	Description
cookie_name	String	Specifies the cookie name. The name can contain a maximum of 255 characters, including letters, digits, underscores (_), hyphens (-), and periods (.). Note: This parameter will take effect only when type is set to APP_COOKIE. Otherwise, an error will be returned. This parameter is unsupported. Please do not use it.
type	String	Specifies the sticky session type. The value can be SOURCE_IP, HTTP_COOKIE, or APP_COOKIE. Note: If the protocol of the backend server group is TCP or UDP, only SOURCE_IP takes effect. If the protocol of the backend server group is HTTP or HTTPS, the value can only be HTTP_COOKIE.
persistence_timeout	Integer	Specifies the stickiness duration, in minutes. This parameter will not take effect when type is set to APP_COOKIE. If the protocol of the backend server group is TCP, UDP, or QUIC, 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. QUIC protocol is not supported.

**Table 14** SlowStart
Parameter	Type	Description
enable	Boolean	Specifies whether to enable slow start. true: Enable slow start. false: Disable slow start. 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

Changing the load balancing algorithm of a backend server group

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" : {
    "type" : "",
    "vpc_id" : "",
    "lb_algorithm" : "LEAST_CONNECTIONS",
    "protocol" : "TCP",
    "description" : "My pool update",
    "admin_state_up" : true,
    "member_deletion_protection_enable" : false,
    "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",
    "pool_health" : {
      "minimum_healthy_member_count" : 0
    }
  },
  "request_id" : "8f40128b-c72b-4b64-986a-f7e2c633d75f"
}