Adding Scaling Strategy for ScaledJob (kedacore#1227)

Signed-off-by: Tsuyoshi Ushio <[email protected]>

api/v1alpha1/scaledjob_types.go

@@ -36,7 +36,9 @@ type ScaledJobSpec struct {
 	// +optional
 	EnvSourceContainerName string `json:"envSourceContainerName,omitempty"`
 	// +optional
-	MaxReplicaCount *int32          `json:"maxReplicaCount,omitempty"`
+	MaxReplicaCount *int32 `json:"maxReplicaCount,omitempty"`
+	// +optional
+	ScalingStrategy ScalingStrategy `json:"scalingStrategy,omitempty"`
 	Triggers        []ScaleTriggers `json:"triggers"`
 }
 
@@ -57,6 +59,17 @@ type ScaledJobList struct {
 	Items           []ScaledJob `json:"items"`
 }
 
+// ScalingStrategy defines the strategy of Scaling
+// +optional
+type ScalingStrategy struct {
+	// +optional
+	Strategy string `json:"strategy,omitempty"`
+	// +optional
+	CustomScalingQueueLengthDeduction *int32 `json:"customScalingQueueLengthDeduction,omitempty"`
+	// +optional
+	CustomScalingRunningJobPercentage string `json:"customScalingRunningJobPercentage,omitempty"`
+}
+
 func init() {
 	SchemeBuilder.Register(&ScaledJob{}, &ScaledJobList{})
 }

config/crd/bases/keda.sh_scaledjobs.yaml

@@ -6343,6 +6343,17 @@ spec:
               pollingInterval:
                 format: int32
                 type: integer
+              scalingStrategy:
+                description: ScalingStrategy defines the strategy of Scaling
+                properties:
+                  customScalingQueueLengthDeduction:
+                    format: int32
+                    type: integer
+                  customScalingRunningJobPercentage:
+                    type: string
+                  strategy:
+                    type: string
+                type: object
               successfulJobsHistoryLimit:
                 format: int32
                 type: integer

pkg/scaling/executor/scale_jobs.go

@@ -3,6 +3,7 @@ package executor
 import (
 	"context"
 	"sort"
+	"strconv"
 
 	"github.com/go-logr/logr"
 	batchv1 "k8s.io/api/batch/v1"
@@ -12,6 +13,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 
+	"github.com/kedacore/keda/api/v1alpha1"
 	kedav1alpha1 "github.com/kedacore/keda/api/v1alpha1"
 	version "github.com/kedacore/keda/version"
 )
@@ -27,12 +29,7 @@ func (e *scaleExecutor) RequestJobScale(ctx context.Context, scaledJob *kedav1al
 	runningJobCount := e.getRunningJobCount(scaledJob)
 	logger.Info("Scaling Jobs", "Number of running Jobs", runningJobCount)
 
-	var effectiveMaxScale int64
-	if (maxScale + runningJobCount) > scaledJob.MaxReplicaCount() {
-		effectiveMaxScale = scaledJob.MaxReplicaCount() - runningJobCount
-	} else {
-		effectiveMaxScale = maxScale
-	}
+	effectiveMaxScale := NewScalingStrategy(logger, scaledJob).GetEffectiveMaxScale(maxScale, runningJobCount, scaledJob.MaxReplicaCount())
 
 	if effectiveMaxScale < 0 {
 		effectiveMaxScale = 0
@@ -227,3 +224,67 @@ func (e *scaleExecutor) getFinishedJobConditionType(j *batchv1.Job) batchv1.JobC
 	}
 	return ""
 }
+
+// NewScalingStrategy returns ScalingStrategy instance
+func NewScalingStrategy(logger logr.Logger, scaledJob *v1alpha1.ScaledJob) ScalingStrategy {
+	switch scaledJob.Spec.ScalingStrategy.Strategy {
+	case "custom":
+		logger.V(1).Info("Selecting Scale Strategy", "specified", scaledJob.Spec.ScalingStrategy.Strategy, "selected:", "custom", "customScalingQueueLength", scaledJob.Spec.ScalingStrategy.CustomScalingQueueLengthDeduction, "customScallingRunningJobPercentage", scaledJob.Spec.ScalingStrategy.CustomScalingRunningJobPercentage)
+		var err error
+		if percentage, err := strconv.ParseFloat(scaledJob.Spec.ScalingStrategy.CustomScalingRunningJobPercentage, 64); err == nil {
+			return customScalingStrategy{
+				CustomScalingQueueLengthDeduction: scaledJob.Spec.ScalingStrategy.CustomScalingQueueLengthDeduction,
+				CustomScalingRunningJobPercentage: &percentage,
+			}
+		}
+
+		logger.V(1).Info("Fail to convert CustomScalingRunningJobPercentage into float", "error", err, "CustomScalingRunningJobPercentage", scaledJob.Spec.ScalingStrategy.CustomScalingRunningJobPercentage)
+		logger.V(1).Info("Selecting Scale has been changed", "selected", "default")
+		return defaultScalingStrategy{}
+
+	case "accurate":
+		logger.V(1).Info("Selecting Scale Strategy", "specified", scaledJob.Spec.ScalingStrategy.Strategy, "selected", "accurate")
+		return accurateScalingStrategy{}
+	default:
+		logger.V(1).Info("Selecting Scale Strategy", "specified", scaledJob.Spec.ScalingStrategy.Strategy, "selected", "default")
+		return defaultScalingStrategy{}
+	}
+}
+
+// ScalingStrategy is an interface for switching scaling algorithm
+type ScalingStrategy interface {
+	GetEffectiveMaxScale(maxScale, runningJobCount, maxReplicaCount int64) int64
+}
+
+type defaultScalingStrategy struct {
+}
+
+func (s defaultScalingStrategy) GetEffectiveMaxScale(maxScale, runningJobCount, maxReplicaCount int64) int64 {
+	return maxScale - runningJobCount
+}
+
+type customScalingStrategy struct {
+	CustomScalingQueueLengthDeduction *int32
+	CustomScalingRunningJobPercentage *float64
+}
+
+func (s customScalingStrategy) GetEffectiveMaxScale(maxScale, runningJobCount, maxReplicaCount int64) int64 {
+	return min(maxScale-int64(*s.CustomScalingQueueLengthDeduction)-int64(float64(runningJobCount)*(*s.CustomScalingRunningJobPercentage)), maxReplicaCount)
+}
+
+type accurateScalingStrategy struct {
+}
+
+func (s accurateScalingStrategy) GetEffectiveMaxScale(maxScale, runningJobCount, maxReplicaCount int64) int64 {
+	if (maxScale + runningJobCount) > maxReplicaCount {
+		return maxReplicaCount - runningJobCount
+	}
+	return maxScale
+}
+
+func min(x, y int64) int64 {
+	if x > y {
+		return y
+	}
+	return x
+}

pkg/scaling/executor/scale_jobs_test.go

@@ -45,6 +45,67 @@ func TestCleanUpNormalCase(t *testing.T) {
 	assert.True(t, ok)
 }
 
+func TestNewNewScalingStrategy(t *testing.T) {
+	logger := logf.Log.WithName("ScaledJobTest")
+	strategy := NewScalingStrategy(logger, getMockScaledJobWithStrategy("custom", "custom", int32(10), "0"))
+	assert.Equal(t, "executor.customScalingStrategy", fmt.Sprintf("%T", strategy))
+	strategy = NewScalingStrategy(logger, getMockScaledJobWithStrategy("accurate", "accurate", int32(0), "0"))
+	assert.Equal(t, "executor.accurateScalingStrategy", fmt.Sprintf("%T", strategy))
+	strategy = NewScalingStrategy(logger, getMockScaledJobWithDefaultStrategy("default"))
+	assert.Equal(t, "executor.defaultScalingStrategy", fmt.Sprintf("%T", strategy))
+	strategy = NewScalingStrategy(logger, getMockScaledJobWithStrategy("default", "default", int32(0), "0"))
+	assert.Equal(t, "executor.defaultScalingStrategy", fmt.Sprintf("%T", strategy))
+}
+
+func TestDefaultScalingStrategy(t *testing.T) {
+	logger := logf.Log.WithName("ScaledJobTest")
+	strategy := NewScalingStrategy(logger, getMockScaledJobWithDefaultStrategy("default"))
+	// maxScale doesn't exceed MaxReplicaCount. You can ignore on this sceanrio
+	assert.Equal(t, int64(1), strategy.GetEffectiveMaxScale(3, 2, 5))
+	assert.Equal(t, int64(2), strategy.GetEffectiveMaxScale(2, 0, 5))
+}
+
+func TestCustomScalingStrategy(t *testing.T) {
+	logger := logf.Log.WithName("ScaledJobTest")
+	customScalingQueueLengthDeduction := int32(1)
+	customScalingRunningJobPercentage := "0.5"
+	strategy := NewScalingStrategy(logger, getMockScaledJobWithStrategy("custom", "custom", customScalingQueueLengthDeduction, customScalingRunningJobPercentage))
+	// maxScale doesn't exceed MaxReplicaCount. You can ignore on this sceanrio
+	assert.Equal(t, int64(1), strategy.GetEffectiveMaxScale(3, 2, 5))
+	assert.Equal(t, int64(9), strategy.GetEffectiveMaxScale(10, 0, 10))
+	strategy = NewScalingStrategy(logger, getMockScaledJobWithCustomStrategyWithNilParameter("custom", "custom"))
+
+	// If you don't set the two parameters is the same behavior as DefaultStrategy
+	assert.Equal(t, int64(1), strategy.GetEffectiveMaxScale(3, 2, 5))
+	assert.Equal(t, int64(2), strategy.GetEffectiveMaxScale(2, 0, 5))
+
+	// Empty String will be DefaultStrategy
+	customScalingQueueLengthDeduction = int32(1)
+	customScalingRunningJobPercentage = ""
+	strategy = NewScalingStrategy(logger, getMockScaledJobWithStrategy("custom", "custom", customScalingQueueLengthDeduction, customScalingRunningJobPercentage))
+	assert.Equal(t, "executor.defaultScalingStrategy", fmt.Sprintf("%T", strategy))
+
+	// Set 0 as customScalingRunningJobPercentage
+	customScalingQueueLengthDeduction = int32(2)
+	customScalingRunningJobPercentage = "0"
+	strategy = NewScalingStrategy(logger, getMockScaledJobWithStrategy("custom", "custom", customScalingQueueLengthDeduction, customScalingRunningJobPercentage))
+	assert.Equal(t, int64(1), strategy.GetEffectiveMaxScale(3, 2, 5))
+
+	// Exceed the MaxReplicaCount
+	customScalingQueueLengthDeduction = int32(-2)
+	customScalingRunningJobPercentage = "0"
+	strategy = NewScalingStrategy(logger, getMockScaledJobWithStrategy("custom", "custom", customScalingQueueLengthDeduction, customScalingRunningJobPercentage))
+	assert.Equal(t, int64(4), strategy.GetEffectiveMaxScale(3, 2, 4))
+}
+
+func TestAccurateScalingStrategy(t *testing.T) {
+	logger := logf.Log.WithName("ScaledJobTest")
+	strategy := NewScalingStrategy(logger, getMockScaledJobWithStrategy("accurate", "accurate", 0, "0"))
+	// maxScale doesn't exceed MaxReplicaCount. You can ignore on this sceanrio
+	assert.Equal(t, int64(3), strategy.GetEffectiveMaxScale(3, 2, 5))
+	assert.Equal(t, int64(3), strategy.GetEffectiveMaxScale(5, 2, 5))
+}
+
 func TestCleanUpMixedCaseWithSortByTime(t *testing.T) {
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
@@ -151,6 +212,40 @@ func getMockScaledJobWithDefault() *kedav1alpha1.ScaledJob {
 	return scaledJob
 }
 
+func getMockScaledJobWithStrategy(name, scalingStrategy string, customScalingQueueLengthDeduction int32, customScalingRunningJobPercentage string) *kedav1alpha1.ScaledJob {
+	scaledJob := &kedav1alpha1.ScaledJob{
+		Spec: kedav1alpha1.ScaledJobSpec{
+			ScalingStrategy: kedav1alpha1.ScalingStrategy{
+				Strategy:                          scalingStrategy,
+				CustomScalingQueueLengthDeduction: &customScalingQueueLengthDeduction,
+				CustomScalingRunningJobPercentage: customScalingRunningJobPercentage,
+			},
+		},
+	}
+	scaledJob.ObjectMeta.Name = name
+	return scaledJob
+}
+
+func getMockScaledJobWithCustomStrategyWithNilParameter(name, scalingStrategy string) *kedav1alpha1.ScaledJob {
+	scaledJob := &kedav1alpha1.ScaledJob{
+		Spec: kedav1alpha1.ScaledJobSpec{
+			ScalingStrategy: kedav1alpha1.ScalingStrategy{
+				Strategy: scalingStrategy,
+			},
+		},
+	}
+	scaledJob.ObjectMeta.Name = name
+	return scaledJob
+}
+
+func getMockScaledJobWithDefaultStrategy(name string) *kedav1alpha1.ScaledJob {
+	scaledJob := &kedav1alpha1.ScaledJob{
+		Spec: kedav1alpha1.ScaledJobSpec{},
+	}
+	scaledJob.ObjectMeta.Name = name
+	return scaledJob
+}
+
 func getMockClient(t *testing.T, ctrl *gomock.Controller, jobs *[]mockJobParameter, deletedJobName *map[string]string) *mock_client.MockClient {
 	client := mock_client.NewMockClient(ctrl)
 	client.EXPECT().