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    ENS:SetLoadBalancerTCPListenerAttribute

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    ENS:SetLoadBalancerTCPListenerAttribute

    Last Updated:Aug 14, 2026

    Modifies the configuration of a TCP listener.

    Operation description

    • API call rate limit: 100 calls per second.

    • Per-user call rate limit: 10 calls per second.

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    RAM authorization

    The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

    • Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.

    • API: The API that you can call to perform the action.

    • Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.

    • Resource type: The type of the resource that supports authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.

      • For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.

      • For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.

    • Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.

    • Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

    Action

    Access level

    Resource type

    Condition key

    Dependent action

    ens:SetLoadBalancerTCPListenerAttribute

    update

    *All Resource

    *

    		 None None

    Request parameters

    Parameter

    Type

    Required

    Description

    Example
    LoadBalancerId

    string

    Yes

    The ID of the load balancing instance.

    lb-5snthcyu1x10g7tywj7iu****
    ListenerPort

    integer

    Yes

    The listener port whose attributes you want to modify. Valid values: 1 to 65535.

    80
    Description

    string

    No

    The description of the listener. The description must be 1 to 80 characters in length.

    Note

    The description cannot start with http:// or https://.

    example
    Scheduler

    string

    No

    The scheduling algorithm. Valid values:

    • wrr: Backend servers with higher weights receive more requests.

    • wlc: Requests are distributed based on the weight and actual load (number of connections) of each backend server. When the weights are the same, backend servers with fewer connections receive more requests.

    • rr: Requests are distributed to backend servers in sequence.

    • sch: Consistent hashing based on source IP addresses. Requests from the same source IP address are distributed to the same backend server.

    • tch: Consistent hashing based on four factors: source IP address, destination IP address, source port, and destination port. Requests from the same flow are distributed to the same backend server.

    Valid values:

    • rr :

      round-robin.

    • wrr :

      weighted round-robin.

    • tch :

      four-element consistent hashing.

    • sch :

      source IP consistent hashing.

    • wlc :

      weighted least connections.

    wrr
    PersistenceTimeout

    integer

    No

    The timeout period of session persistence.

    • Default value: 0, which indicates that session persistence is disabled.

    • Valid values: 0 to 3600.

    • Unit: seconds.

    0
    EstablishedTimeout

    integer

    No

    The connection timeout period. Valid values: 10 to 900. Unit: seconds.

    500
    HealthyThreshold

    integer

    No

    The number of consecutive successful health checks required before the health check status of a backend server changes from fail (unreachable) to success (reachable). Valid values: 2 to 10.

    4
    UnhealthyThreshold

    integer

    No

    The number of consecutive failed health checks required before the health check status of a backend server changes from success (reachable) to fail (unreachable). Valid values: 2 to 10.

    4
    HealthCheckConnectTimeout

    integer

    No

    The maximum amount of time to wait for a response from a health check. If the backend ENS does not respond within the specified time, the health check fails.

    • Default value: 5 seconds.

    • Valid values: 1 to 300.

    • Unit: seconds.

    Note

    If the value of HealthCheckConnectTimeout is less than the value of HealthCheckInterval, HealthCheckConnectTimeout becomes invalid and the timeout period is set to the value of HealthCheckInterval.

    100
    HealthCheckConnectPort

    integer

    No

    The port used for health checks. Valid values: 1 to 65535. If this parameter is not set, the backend service port (BackendServerPort) is used.

    8000
    HealthCheckInterval

    integer

    No

    The interval between two consecutive health checks. Valid values: 1 to 50. Unit: seconds.

    5
    HealthCheckDomain

    string

    No

    The domain name used for health checks.

    www.aliyundoc.com
    HealthCheckURI

    string

    No

    The URI used for health checks. The URI must be 1 to 80 characters in length.

    Note

    The URI cannot be only / but must start with /.

    /aliyundoc/index.html
    HealthCheckHttpCode

    string

    No

    The HTTP status code for a Normal health check. Valid values:

    • http_2xx (default).

    • http_3xx.

    • http_4xx.

    • http_5xx.

    http_2xx
    HealthCheckType

    string

    No

    The health check type. Valid values:

    • tcp (default).

    • http.

    Valid values:

    • tcp :

      TCP.

    • http :

      HTTP.

    tcp
    EipTransmit

    string

    No

    Specifies whether to enable EIP pass-through. Valid values:

    • on: Enabled.

    • off (default): Disabled.

    Valid values:

    • off :

      disabled.

    • on :

      enabled.

    on

    Response elements

    Element

    Type

    Description

    Example

    object

    Schema of Response

    RequestId

    string

    The request ID.

    06F00FBB-3D9E-4CCE-9D43-1A6946A75456

    Examples

    Success response

    JSON format

    {
  "RequestId": "06F00FBB-3D9E-4CCE-9D43-1A6946A75456"
}

    Error codes

    HTTP status code

    Error code

    Error message

    Description
    400 ens.interface.error An error occurred while call the API.
    400 Invalid%s The specified parameter %s is invalid.
    400 Missing%s You must specify the parameter %s.
    400 LoadBalancerNotFound The input parameter loadBalancerId that is not found.
    400 IncorrectInstanceStatus The current status of the resource does not support this operation. The current operation is not supported. The disk is being reset.
    400 ListenerNotFound The input parameter listener that is not found.
    400 IncorrectListenerStatus The current status of the resource does not support this operation. The listener status is incorrect.
    400 NoPermission Permission denied.
    400 InvalidParameter.%s The specified field %s invalid. Please check it again.

    See Error Codes for a complete list.

    Release notes

    See Release Notes for a complete list.