Merge pull request #18630 from kubernetes/revert-18315-hpa-tolerance-config

cmd/kube-controller-manager/app/controllermanager.go

@@ -365,11 +365,7 @@ func (s *CMServer) Run(_ []string) error {
 				metrics.DefaultHeapsterService,
 				metrics.DefaultHeapsterPort,
 			)
-			// TODO parameterize tolerance/downscale/upscale options.
-			tolerance := 1.0
-			downScale := time.Duration(5) * time.Second
-			upScale := time.Duration(3) * time.Second
-			podautoscaler.NewHorizontalController(kubeClient, metricsClient, tolerance, downScale, upScale).
+			podautoscaler.NewHorizontalController(hpaClient, metricsClient).
 				Run(s.HorizontalPodAutoscalerSyncPeriod)
 		}
 

pkg/controller/podautoscaler/horizontal.go

@@ -31,40 +31,30 @@ import (
 	"k8s.io/kubernetes/pkg/util"
 )
 
+const (
+	// Usage shoud exceed the tolerance before we start downscale or upscale the pods.
+	// TODO: make it a flag or HPA spec element.
+	tolerance = 0.1
+)
+
 type HorizontalController struct {
 	client        client.Interface
 	metricsClient metrics.MetricsClient
 	eventRecorder record.EventRecorder
-	tolerance                float64
-	downscaleForbiddenWindow time.Duration
-	upscaleForbiddenWindow   time.Duration
 }
 
-func NewHorizontalController(client client.Interface, metricsClient metrics.MetricsClient, tol float64, dScale, uScale time.Duration) *HorizontalController {
+var downscaleForbiddenWindow = 5 * time.Minute
+var upscaleForbiddenWindow = 3 * time.Minute
+
+func NewHorizontalController(client client.Interface, metricsClient metrics.MetricsClient) *HorizontalController {
 	broadcaster := record.NewBroadcaster()
 	broadcaster.StartRecordingToSink(client.Events(""))
 	recorder := broadcaster.NewRecorder(api.EventSource{Component: "horizontal-pod-autoscaler"})
 
-	if tol < 0 || tol > 1 {
-		glog.Warningf("Invalid tolerance provided %v using default.", tol)
-		tol = .1
-	}
-	if uScale == 0*time.Second {
-		glog.Warningf("Invalid upscale value provided, %v using default.", uScale)
-		uScale = 3 * time.Minute
-	}
-	if dScale == 0*time.Second {
-		glog.Warningf("Invalid downscale value provided, %v using default.", dScale)
-		dScale = 5 * time.Minute
-	}
-	glog.V(2).Infof("Created Horizontal Controller with downscale %v, upscale %v, and tolerance %v", tol, uScale, dScale)
 	return &HorizontalController{
 		client:        client,
 		metricsClient: metricsClient,
 		eventRecorder: recorder,
-		tolerance:                tol,
-		downscaleForbiddenWindow: dScale,
-		upscaleForbiddenWindow:   uScale,
 	}
 }
 
@@ -93,7 +83,7 @@ func (a *HorizontalController) computeReplicasForCPUUtilization(hpa extensions.H
 	}
 
 	usageRatio := float64(*currentUtilization) / float64(hpa.Spec.CPUUtilization.TargetPercentage)
-	if math.Abs(1.0-usageRatio) > a.tolerance {
+	if math.Abs(1.0-usageRatio) > tolerance {
 		return int(math.Ceil(usageRatio * float64(currentReplicas))), currentUtilization, timestamp, nil
 	} else {
 		return currentReplicas, currentUtilization, timestamp, nil
@@ -135,7 +125,7 @@ func (a *HorizontalController) reconcileAutoscaler(hpa extensions.HorizontalPodA
 		// and there was no rescaling in the last downscaleForbiddenWindow.
 		if desiredReplicas < currentReplicas &&
 			(hpa.Status.LastScaleTime == nil ||
-				hpa.Status.LastScaleTime.Add(a.downscaleForbiddenWindow).Before(timestamp)) {
+				hpa.Status.LastScaleTime.Add(downscaleForbiddenWindow).Before(timestamp)) {
 			rescale = true
 		}
 
@@ -143,7 +133,7 @@ func (a *HorizontalController) reconcileAutoscaler(hpa extensions.HorizontalPodA
 		// and there was no rescaling in the last upscaleForbiddenWindow.
 		if desiredReplicas > currentReplicas &&
 			(hpa.Status.LastScaleTime == nil ||
-				hpa.Status.LastScaleTime.Add(a.upscaleForbiddenWindow).Before(timestamp)) {
+				hpa.Status.LastScaleTime.Add(upscaleForbiddenWindow).Before(timestamp)) {
 			rescale = true
 		}
 	}

pkg/controller/podautoscaler/horizontal_test.go

@@ -20,7 +20,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"math"
 	"testing"
 	"time"
 
@@ -33,14 +32,9 @@ import (
 	"k8s.io/kubernetes/pkg/controller/podautoscaler/metrics"
 	"k8s.io/kubernetes/pkg/runtime"
 
-	glog "github.com/golang/glog"
-	"github.com/stretchr/testify/assert"
 	heapster "k8s.io/heapster/api/v1/types"
-)
 
-// unit tests need tolerance awareness to calibrate.
-const (
-	tolerance = .1
+	"github.com/stretchr/testify/assert"
 )
 
 func (w fakeResponseWrapper) DoRaw() ([]byte, error) {
@@ -212,7 +206,7 @@ func (tc *testCase) verifyResults(t *testing.T) {
 func (tc *testCase) runTest(t *testing.T) {
 	testClient := tc.prepareTestClient(t)
 	metricsClient := metrics.NewHeapsterMetricsClient(testClient, metrics.DefaultHeapsterNamespace, metrics.DefaultHeapsterScheme, metrics.DefaultHeapsterService, metrics.DefaultHeapsterPort)
-	hpaController := NewHorizontalController(testClient, metricsClient, tolerance, time.Second, time.Second)
+	hpaController := NewHorizontalController(testClient, metricsClient)
 	err := hpaController.reconcileAutoscalers()
 	assert.Equal(t, nil, err)
 	if tc.verifyEvents {
@@ -366,64 +360,4 @@ func TestEventNotCreated(t *testing.T) {
 	tc.runTest(t)
 }
 
-// TestComputedToleranceAlgImplementation is a regression test which
-// back-calculates a minimal percentage for downscaling based on a small percentage
-// increase in pod utilization which is calibrated against the tolerance value.
-func TestComputedToleranceAlgImplementation(t *testing.T) {
-
-	startPods := 10
-	// 150 mCPU per pod.
-	totalUsedCPUOfAllPods := uint64(startPods * 150)
-	// Each pod starts out asking for 2X what is really needed.
-	// This means we will have a 50% ratio of used/requested
-	totalRequestedCPUOfAllPods := 2 * totalUsedCPUOfAllPods
-	requestedToUsed := float64(totalRequestedCPUOfAllPods / totalUsedCPUOfAllPods)
-	// Spread the amount we ask over 10 pods.  We can add some jitter later in reportedLevels.
-	perPodRequested := int(totalRequestedCPUOfAllPods) / startPods
-
-	// Force a minimal scaling event by satisfying  (tolerance < 1 - resourcesUsedRatio).
-	target := math.Abs(1/(requestedToUsed*(1-tolerance))) + .01
-	finalCpuPercentTarget := int(target * 100)
-	resourcesUsedRatio := float64(totalUsedCPUOfAllPods) / float64(float64(totalRequestedCPUOfAllPods)*target)
-	// the autoscaler will compare this vs. tolearnce.  Lets calculate the usageRatio, which will be
-	// compared w tolerance.
-	usageRatioToleranceValue := float64(1 - resourcesUsedRatio)
-	// i.e. .60 * 20 -> scaled down expectation.
-	finalPods := math.Ceil(resourcesUsedRatio * float64(startPods))
-
-	glog.Infof("To breach tolerance %f we will create a utilization ratio difference of %f", tolerance, usageRatioToleranceValue)
-	tc := testCase{
-		minReplicas:     0,
-		maxReplicas:     1000,
-		initialReplicas: startPods,
-		desiredReplicas: int(finalPods),
-		CPUTarget:       finalCpuPercentTarget,
-		reportedLevels: []uint64{
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-			totalUsedCPUOfAllPods / 10,
-		},
-		reportedCPURequests: []resource.Quantity{
-			resource.MustParse(fmt.Sprint(perPodRequested+100) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested-100) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested+10) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested-10) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested+2) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested-2) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested+1) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested-1) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested) + "m"),
-			resource.MustParse(fmt.Sprint(perPodRequested) + "m"),
-		},
-	}
-	tc.runTest(t)
-}
-
-// TODO: add more tests, e.g., enforcement of upscal/downscale window.
+// TODO: add more tests