# istio_new_lb_algorithm_default.yaml
apiVersion: release-notes/v2
kind: feature
area: traffic-management

releaseNotes:
  - |
    **Updated** Istio's default load balancing algorithm from `ROUND_ROBIN` to `LEAST_REQUEST`.
    The `ROUND_ROBIN` algorithm can lead to overburdened endpoints, especially when weights
    are used. The `LEAST_REQUEST` algorithm, distributes more evenly across and is far less
    likely to overburden endpoints. A number of experiments (by both the Istio and
    Envoy teams) have shown that `LEAST_REQUEST` outperforms `ROUND_ROBIN` in virtually all
    cases, with little/no downsides. It's generally considered a drop-in replacement for
    ROUND_ROBIN.
    
    `ROUND_ROBIN` will continue to be supported if explicitly specified. To restore
    `ROUND_ROBIN` as the default, set the istiod environment variable
    `ENABLE_LEGACY_LB_ALGORITHM_DEFAULT=true`.