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feat(loadbalancer): support slow start aggression and minWeightPercent
Expose the `aggression` and `minWeightPercent` parameters of Envoy's SlowStartConfig via BackendTrafficPolicy. Previously only the slow start `window` was configurable, which limited users to a linear ramp-up. `aggression` enables polynomial/exponential ramp-up curves, and `minWeightPercent` guards against starvation when the scaled weight would otherwise approach zero. Addresses the existing TODO in the SlowStart API type. Signed-off-by: Adam Buran <aburan28@gmail.com>
1 parent f404a9c commit 3144c52

24 files changed

Lines changed: 1611 additions & 87 deletions

‎api/v1alpha1/loadbalancer_types.go‎

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@@ -287,11 +287,35 @@ const (
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type SlowStart struct {
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// Window defines the duration of the warm up period for newly added host.
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// During slow start window, traffic sent to the newly added hosts will gradually increase.
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// Currently only supports linear growth of traffic. For additional details,
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// For additional details,
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// see https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/cluster/v3/cluster.proto#config-cluster-v3-cluster-slowstartconfig
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// +kubebuilder:validation:Required
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Window *gwapiv1.Duration `json:"window"`
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// TODO: Add support for non-linear traffic increases based on user usage.
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// Aggression controls the speed at which the endpoint weight ramps up during the
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// slow start window. The endpoint weight is scaled by the time factor raised to
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// the power of (1 / aggression). Values greater than 1.0 result in a faster
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// initial ramp-up followed by a slower approach to the full weight (exponential),
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// while values less than 1.0 result in a slower initial ramp-up followed by a
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// faster approach to the full weight (logarithmic).
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//
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// Must be a positive decimal number (e.g. "1.0", "1.5", "2.0"). If unset,
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// Envoy uses its default of 1.0, which produces a linear ramp-up.
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//
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// +optional
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// +kubebuilder:validation:Pattern=`^([0-9]+(\.[0-9]+)?|\.[0-9]+)$`
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// +kubebuilder:validation:XValidation:rule="self != '0' && self != '0.0' && self != '.0'",message="aggression must be greater than 0"
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Aggression *string `json:"aggression,omitempty"`
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// MinWeightPercent specifies the minimum percent of origin weight that avoids
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// too small new weight when an endpoint is in slow start window. This ensures
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// that the EDF scheduler has a reasonable deadline. If unset, Envoy uses its
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// default of 10%.
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//
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// +optional
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// +kubebuilder:validation:Minimum=0
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// +kubebuilder:validation:Maximum=100
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MinWeightPercent *uint32 `json:"minWeightPercent,omitempty"`
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}
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// ZoneAware defines the configuration related to the distribution of requests between locality zones.

‎api/v1alpha1/zz_generated.deepcopy.go‎

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‎charts/gateway-crds-helm/templates/generated/gateway.envoyproxy.io_backendtrafficpolicies.yaml‎

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@@ -1048,11 +1048,37 @@ spec:
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If set, during slow start window, traffic sent to the newly added hosts will gradually increase.
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Supported for RoundRobin, LeastRequest, and BackendUtilization load balancers.
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properties:
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aggression:
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description: |-
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Aggression controls the speed at which the endpoint weight ramps up during the
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slow start window. The endpoint weight is scaled by the time factor raised to
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the power of (1 / aggression). Values greater than 1.0 result in a faster
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initial ramp-up followed by a slower approach to the full weight (exponential),
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while values less than 1.0 result in a slower initial ramp-up followed by a
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faster approach to the full weight (logarithmic).
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Must be a positive decimal number (e.g. "1.0", "1.5", "2.0"). If unset,
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Envoy uses its default of 1.0, which produces a linear ramp-up.
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pattern: ^([0-9]+(\.[0-9]+)?|\.[0-9]+)$
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type: string
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x-kubernetes-validations:
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- message: aggression must be greater than 0
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rule: self != '0' && self != '0.0' && self != '.0'
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minWeightPercent:
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description: |-
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MinWeightPercent specifies the minimum percent of origin weight that avoids
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too small new weight when an endpoint is in slow start window. This ensures
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that the EDF scheduler has a reasonable deadline. If unset, Envoy uses its
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default of 10%.
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format: int32
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maximum: 100
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minimum: 0
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type: integer
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window:
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description: |-
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Window defines the duration of the warm up period for newly added host.
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During slow start window, traffic sent to the newly added hosts will gradually increase.
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Currently only supports linear growth of traffic. For additional details,
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For additional details,
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see https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/cluster/v3/cluster.proto#config-cluster-v3-cluster-slowstartconfig
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pattern: ^([0-9]{1,5}(h|m|s|ms)){1,4}$
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type: string

‎charts/gateway-crds-helm/templates/generated/gateway.envoyproxy.io_envoyextensionpolicies.yaml‎

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@@ -1135,11 +1135,38 @@ spec:
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If set, during slow start window, traffic sent to the newly added hosts will gradually increase.
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Supported for RoundRobin, LeastRequest, and BackendUtilization load balancers.
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properties:
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aggression:
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description: |-
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Aggression controls the speed at which the endpoint weight ramps up during the
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slow start window. The endpoint weight is scaled by the time factor raised to
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the power of (1 / aggression). Values greater than 1.0 result in a faster
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initial ramp-up followed by a slower approach to the full weight (exponential),
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while values less than 1.0 result in a slower initial ramp-up followed by a
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faster approach to the full weight (logarithmic).
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Must be a positive decimal number (e.g. "1.0", "1.5", "2.0"). If unset,
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Envoy uses its default of 1.0, which produces a linear ramp-up.
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pattern: ^([0-9]+(\.[0-9]+)?|\.[0-9]+)$
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type: string
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x-kubernetes-validations:
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- message: aggression must be greater than 0
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rule: self != '0' && self != '0.0' && self !=
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'.0'
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minWeightPercent:
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description: |-
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MinWeightPercent specifies the minimum percent of origin weight that avoids
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too small new weight when an endpoint is in slow start window. This ensures
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that the EDF scheduler has a reasonable deadline. If unset, Envoy uses its
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default of 10%.
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format: int32
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maximum: 100
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minimum: 0
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type: integer
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window:
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description: |-
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Window defines the duration of the warm up period for newly added host.
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During slow start window, traffic sent to the newly added hosts will gradually increase.
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Currently only supports linear growth of traffic. For additional details,
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For additional details,
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see https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/cluster/v3/cluster.proto#config-cluster-v3-cluster-slowstartconfig
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pattern: ^([0-9]{1,5}(h|m|s|ms)){1,4}$
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type: string

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