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    ENS:DescribeLoadBalancerHTTPListenerAttribute

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    ENS:DescribeLoadBalancerHTTPListenerAttribute

    Last Updated:Mar 27, 2026

    Queries the configuration of an HTTP listener.

    Operation description

    • up to 100 times per second per account.

    • up to 10 times per second per user.

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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:DescribeLoadBalancerHTTPListenerAttribute

    get

    *All Resource

    *

    		 None None

    Request parameters

    Parameter

    Type

    Required

    Description

    Example
    ListenerPort

    integer

    Yes

    The listener port that you want to query. Valid values: 1 to 65535.

    80
    LoadBalancerId

    string

    Yes

    The ID of the ELB instance.

    lb-5snthcyu1x10g7tywj7iu****

    Response elements

    Element

    Type

    Description

    Example

    object

    Schema of Response

    RequestId

    string

    The ID of the request.

    473469C7-AA6F-4DC5-B3DB-A3DC0DE3C83E
    ListenerPort

    integer

    The listener port.

    80
    Status

    string

    The status of the listener. Valid values:

    • Running

    • Stopped

    • Starting

    • Configuring

    • Stopping

    Running
    Bandwidth

    integer

    The peak bandwidth of the Edge Load Balancer (ELB) instance. The default value is -1, which indicates that the bandwidth is not limited.

    -1
    Scheduler

    string

    The routing algorithm. Valid values:

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

    • wlc: Requests are distributed based on the weight and load of each backend server. The load refers to the number of connections to a backend server. If two backend servers have the same weight, the backend server that has fewer connections receives more requests.

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

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

    • qch: consistent hashing that is based on QUIC connection IDs. Requests that contain the same QUIC connection ID are distributed to the same backend server.

    • iqch: consistent hashing that is based on specific three bytes of the iQUIC CIDs. Requests whose second to fourth bytes are the same are distributed to the same backend server.

    wrr
    HealthCheck

    string

    Indicates whether the health check feature is enabled. Valid values:

    • on

    • off

    on
    HealthyThreshold

    integer

    The number of consecutive successful health checks that must occur before an unhealthy and inaccessible backend server is declared healthy and accessible. Valid values: 2 to 10.

    Note

    This parameter is returned only if you set HealthCheck to on.

    3
    UnhealthyThreshold

    integer

    The number of consecutive failed health checks that must occur before a healthy and accessible backend server is declared unhealthy and inaccessible. Valid values: 2 to 10.

    Note

    This parameter is returned only if you set HealthCheck to on.

    3
    HealthCheckTimeout

    integer

    The timeout period of a health check response. If a backend server does not respond within the specified timeout period, the server fails the health check.

    • Default value: 5.

    • Valid values: 1 to 300.

    • Unit: seconds.

    Note

    • This parameter takes effect only if the HealthCheck parameter is set to on.

    • If the value of HealthCheckTimeout is smaller than the value of HealthCheckInterval, the timeout period specified by HealthCheckTimeout becomes invalid, and the value of HealthCheckInterval is used as the timeout period.

    10
    HealthCheckConnectPort

    integer

    The port that is used for health checks. Valid values: 1 to 65535. If you leave this parameter empty, the port specified by BackendServerPort is used for health checks.

    Note

    This parameter is returned only if you set HealthCheck to on.

    5000
    HealthCheckInterval

    integer

    The interval at which health checks are performed. Valid values: 1 to 50. Unit: seconds.

    Note

    This parameter is returned only if you set HealthCheck to on.

    5
    Description

    string

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

    Note

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

    abc
    ListenerForward

    string

    Indicates whether HTTP-to-HTTPS redirection is enabled. Valid values:

    • on: HTTP-to-HTTPS redirection is enabled.

    • off (default)

    off
    ForwardPort

    integer

    The listener port that is used to redirect HTTP requests to HTTPS.

    10002
    RequestTimeout

    integer

    The timeout period of requests. Default value: 60. Valid values: 1 to 180. Unit: seconds.

    Note

    If no response is received from the backend server within the specified timeout period, ELB returns an HTTP 504 error code to the client.

    60
    IdleTimeout

    integer

    The timeout period for idle connections. Default value: 15. Valid values: 1 to 60. Unit: seconds.

    Note

    If no request is received within the specified timeout period, ELB closes the connection. When another request is received, ELB establishes a new connection.

    15
    HealthCheckHttpCode

    string

    The HTTP status codes for a successful health check. Valid values:

    • http_2xx (default)

    • http_3xx.

    • http_4xx

    • http_5xx

    Note

    This parameter is returned only if you set HealthCheck to on.

    http_2xx
    HealthCheckDomain

    string

    The domain name that is used for health checks.

    Note

    This parameter is returned only if you set HealthCheck to on.

    www.example.com
    HealthCheckURI

    string

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

    Note

    • A URL must start with a forward slash (/) but cannot contain only forward slashes (/).

    • This parameter takes effect only if the HealthCheck parameter is set to on.

    /checkpreload.htm
    ServerCertificateId

    string

    The ID of the server certificate.

    6027667
    HealthCheckMethod

    string

    The health check method used in HTTP health checks. Valid values:

    • head: requests the head of the page.

    • get: requests the specified part of the page and returns the entity body.

    Note

    This parameter is returned only if you set HealthCheck to on.

    head
    XForwardedFor

    string

    Indicates whether the X-Forwarded-For header is used to obtain the real IP address of the client. Valid values:

    • on (default)

    • off

    on

    BackendServerPort

    integer

    The port used by the backend server of the ELB instance. Valid values: 1 to 65535.

    8080

    Examples

    Success response

    JSON format

    {
  "RequestId": "473469C7-AA6F-4DC5-B3DB-A3DC0DE3C83E",
  "ListenerPort": 80,
  "Status": "Running",
  "Bandwidth": -1,
  "Scheduler": "wrr",
  "HealthCheck": "on",
  "HealthyThreshold": 3,
  "UnhealthyThreshold": 3,
  "HealthCheckTimeout": 10,
  "HealthCheckConnectPort": 5000,
  "HealthCheckInterval": 5,
  "Description": "abc",
  "ListenerForward": "off",
  "ForwardPort": 10002,
  "RequestTimeout": 60,
  "IdleTimeout": 15,
  "HealthCheckHttpCode": "http_2xx",
  "HealthCheckDomain": "www.example.com",
  "HealthCheckURI": "/checkpreload.htm",
  "ServerCertificateId": "6027667",
  "HealthCheckMethod": "head",
  "XForwardedFor": "on\n",
  "BackendServerPort": 8080
}

    Error codes

    HTTP status code

    Error code

    Error message

    Description
    400 LoadBalancerNotFound The input parameter loadBalancerId that is not found.
    400 ListenerNotFound Listener is not found. Listener does not exist
    400 ens.interface.error Failed to call API.
    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.