Least Request Load Balancing Policy (proto)

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:

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

extensions.load_balancing_policies.least_request.v3.LeastRequest

[extensions.load_balancing_policies.least_request.v3.LeastRequest proto]

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

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

(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.

active_request_bias

(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.

slow_start_config

(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.

locality_lb_config

(extensions.load_balancing_policies.common.v3.LocalityLbConfig) Configuration for local zone aware load balancing or locality weighted load balancing.