Client-Side Weighted Round Robin Load Balancing Policy (proto)
This extension has the qualified name envoy.load_balancing_policies.client_side_weighted_round_robin
Note
This extension is work-in-progress. Functionality is incomplete and it is not intended for production use.
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.client_side_weighted_round_robin.v3.ClientSideWeightedRoundRobin
Configuration for the client_side_weighted_round_robin LB policy.
This policy differs from the built-in ROUND_ROBIN policy in terms of
how the endpoint weights are determined. In the ROUND_ROBIN policy,
the endpoint weights are sent by the control plane via EDS. However,
in this policy, the endpoint weights are instead determined via qps (queries
per second), eps (errors per second), and utilization metrics sent by the
endpoint using the Open Request Cost Aggregation (ORCA) protocol. Utilization
is determined by using the ORCA application_utilization field, if set, or
else falling back to the cpu_utilization field. All queries count toward qps,
regardless of result. Only failed queries count toward eps. A config
parameter error_utilization_penalty controls the penalty to adjust endpoint
weights using eps and qps. The weight of a given endpoint is computed as:
qps / (utilization + eps/qps * error_utilization_penalty).
See the load balancing architecture overview for more information.
{
"enable_oob_load_report": {...},
"oob_reporting_period": {...},
"blackout_period": {...},
"weight_expiration_period": {...},
"weight_update_period": {...},
"error_utilization_penalty": {...},
"metric_names_for_computing_utilization": []
}
- enable_oob_load_report
(BoolValue) Whether to enable out-of-band utilization reporting collection from the endpoints. By default, per-request utilization reporting is used.
- oob_reporting_period
(Duration) Load reporting interval to request from the server. Note that the server may not provide reports as frequently as the client requests. Used only when enable_oob_load_report is true. Default is 10 seconds.
- blackout_period
(Duration) A given endpoint must report load metrics continuously for at least this long before the endpoint weight will be used. This avoids churn when the set of endpoint addresses changes. Takes effect both immediately after we establish a connection to an endpoint and after weight_expiration_period has caused us to stop using the most recent load metrics. Default is 10 seconds.
- weight_expiration_period
(Duration) If a given endpoint has not reported load metrics in this long, then we stop using the reported weight. This ensures that we do not continue to use very stale weights. Once we stop using a stale value, if we later start seeing fresh reports again, the blackout_period applies. Defaults to 3 minutes.
- weight_update_period
(Duration) How often endpoint weights are recalculated. Values less than 100ms are capped at 100ms. Default is 1 second.
- error_utilization_penalty
(FloatValue) The multiplier used to adjust endpoint weights with the error rate calculated as eps/qps. Configuration is rejected if this value is negative. Default is 1.0.
- metric_names_for_computing_utilization
(repeated string) By default, endpoint weight is computed based on the application_utilization field reported by the endpoint. If that field is not set, then utilization will instead be computed by taking the max of the values of the metrics specified here. For map fields in the ORCA proto, the string will be of the form
<map_field_name>.<map_key>. For example, the stringnamed_metrics.foowill mean to look for the keyfooin the ORCA named_metrics field. If none of the specified metrics are present in the load report, then cpu_utilization is used instead.