.. _envoy_v3_api_file_envoy/extensions/load_balancing_policies/least_request/v3/least_request.proto:

Least Request Load Balancing Policy (proto)
===========================================

.. _extension_envoy.load_balancing_policies.least_request:

This extension has the qualified name ``envoy.load_balancing_policies.least_request``


.. note::
  

  This extension has an unknown security posture and should only be
  used in deployments where both the downstream and upstream are
  trusted.

.. tip::
  This extension extends and can be used with the following extension category:


  - :ref:`envoy.load_balancing_policies <extension_category_envoy.load_balancing_policies>`



  This extension must be configured with one of the following type URLs:



  - :ref:`type.googleapis.com/envoy.extensions.load_balancing_policies.least_request.v3.LeastRequest <envoy_v3_api_msg_extensions.load_balancing_policies.least_request.v3.LeastRequest>`







.. _envoy_v3_api_msg_extensions.load_balancing_policies.least_request.v3.LeastRequest:

extensions.load_balancing_policies.least_request.v3.LeastRequest
----------------------------------------------------------------


:repo:`[extensions.load_balancing_policies.least_request.v3.LeastRequest proto] <api/envoy/extensions/load_balancing_policies/least_request/v3/least_request.proto#L24>`

This configuration allows the built-in LEAST_REQUEST LB policy to be configured via the LB policy
extension point. See the :ref:`load balancing architecture overview
<arch_overview_load_balancing_types>` for more information.



.. code-block:: json
  :force:

  {
    "choice_count": {...},
    "active_request_bias": {...},
    "slow_start_config": {...},
    "locality_lb_config": {...}
  }

.. _envoy_v3_api_field_extensions.load_balancing_policies.least_request.v3.LeastRequest.choice_count:


choice_count
  (`UInt32Value <https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#uint32value>`_) The number of random healthy hosts from which the host with the fewest active requests will
  be chosen. Defaults to 2 so that we perform two-choice selection if the field is not set.


.. _envoy_v3_api_field_extensions.load_balancing_policies.least_request.v3.LeastRequest.active_request_bias:


active_request_bias
  (:ref:`config.core.v3.RuntimeDouble <envoy_v3_api_msg_config.core.v3.RuntimeDouble>`) The following formula is used to calculate the dynamic weights when hosts have different load
  balancing weights:

  `weight = load_balancing_weight / (active_requests + 1)^active_request_bias`

  The larger the active request bias is, the more aggressively active requests will lower the
  effective weight when all host weights are not equal.

  `active_request_bias` must be greater than or equal to 0.0.

  When `active_request_bias == 0.0` the Least Request Load Balancer doesn't consider the number
  of active requests at the time it picks a host and behaves like the Round Robin Load
  Balancer.

  When `active_request_bias > 0.0` the Least Request Load Balancer scales the load balancing
  weight by the number of active requests at the time it does a pick.

  The value is cached for performance reasons and refreshed whenever one of the Load Balancer's
  host sets changes, e.g., whenever there is a host membership update or a host load balancing
  weight change.

  .. note::
    This setting only takes effect if all host weights are not equal.


.. _envoy_v3_api_field_extensions.load_balancing_policies.least_request.v3.LeastRequest.slow_start_config:


slow_start_config
  (:ref:`extensions.load_balancing_policies.common.v3.SlowStartConfig <envoy_v3_api_msg_extensions.load_balancing_policies.common.v3.SlowStartConfig>`) Configuration for slow start mode.
  If this configuration is not set, slow start will not be not enabled.


.. _envoy_v3_api_field_extensions.load_balancing_policies.least_request.v3.LeastRequest.locality_lb_config:


locality_lb_config
  (:ref:`extensions.load_balancing_policies.common.v3.LocalityLbConfig <envoy_v3_api_msg_extensions.load_balancing_policies.common.v3.LocalityLbConfig>`) Configuration for local zone aware load balancing or locality weighted load balancing.