Drop LogarithmicScaleDown after the feature GA-ed in 1.31

Signed-off-by: Maciej Szulik <soltysh@gmail.com>

pkg/controller/controller_utils.go

@@ -880,18 +880,14 @@ func (s ActivePodsWithRanks) Less(i, j int) bool {
 		readyTime1 := podReadyTime(s.Pods[i])
 		readyTime2 := podReadyTime(s.Pods[j])
 		if !readyTime1.Equal(readyTime2) {
-			if !utilfeature.DefaultFeatureGate.Enabled(features.LogarithmicScaleDown) {
+			if s.Now.IsZero() || readyTime1.IsZero() || readyTime2.IsZero() {
 				return afterOrZero(readyTime1, readyTime2)
-			} else {
-				if s.Now.IsZero() || readyTime1.IsZero() || readyTime2.IsZero() {
-					return afterOrZero(readyTime1, readyTime2)
-				}
-				rankDiff := logarithmicRankDiff(*readyTime1, *readyTime2, s.Now)
-				if rankDiff == 0 {
-					return s.Pods[i].UID < s.Pods[j].UID
-				}
-				return rankDiff < 0
 			}
+			rankDiff := logarithmicRankDiff(*readyTime1, *readyTime2, s.Now)
+			if rankDiff == 0 {
+				return s.Pods[i].UID < s.Pods[j].UID
+			}
+			return rankDiff < 0
 		}
 	}
 	// 7. Pods with containers with higher restart counts < lower restart counts
@@ -900,18 +896,14 @@ func (s ActivePodsWithRanks) Less(i, j int) bool {
 	}
 	// 8. Empty creation time pods < newer pods < older pods
 	if !s.Pods[i].CreationTimestamp.Equal(&s.Pods[j].CreationTimestamp) {
-		if !utilfeature.DefaultFeatureGate.Enabled(features.LogarithmicScaleDown) {
+		if s.Now.IsZero() || s.Pods[i].CreationTimestamp.IsZero() || s.Pods[j].CreationTimestamp.IsZero() {
 			return afterOrZero(&s.Pods[i].CreationTimestamp, &s.Pods[j].CreationTimestamp)
-		} else {
-			if s.Now.IsZero() || s.Pods[i].CreationTimestamp.IsZero() || s.Pods[j].CreationTimestamp.IsZero() {
-				return afterOrZero(&s.Pods[i].CreationTimestamp, &s.Pods[j].CreationTimestamp)
-			}
-			rankDiff := logarithmicRankDiff(s.Pods[i].CreationTimestamp, s.Pods[j].CreationTimestamp, s.Now)
-			if rankDiff == 0 {
-				return s.Pods[i].UID < s.Pods[j].UID
-			}
-			return rankDiff < 0
 		}
+		rankDiff := logarithmicRankDiff(s.Pods[i].CreationTimestamp, s.Pods[j].CreationTimestamp, s.Now)
+		if rankDiff == 0 {
+			return s.Pods[i].UID < s.Pods[j].UID
+		}
+		return rankDiff < 0
 	}
 	return false
 }

pkg/controller/controller_utils_test.go

@@ -831,9 +831,8 @@ func TestSortingActivePodsWithRanks(t *testing.T) {
 		ready10Hours                        = pod("ready-10-hours", "", v1.PodRunning, true, 0, 0, then8Hours, then1Month, nil)
 	)
 	equalityTests := []struct {
-		p1                          *v1.Pod
-		p2                          *v1.Pod
-		disableLogarithmicScaleDown bool
+		p1 *v1.Pod
+		p2 *v1.Pod
 	}{
 		{p1: unscheduledPod},
 		{p1: scheduledPendingPod},
@@ -849,7 +848,6 @@ func TestSortingActivePodsWithRanks(t *testing.T) {
 	}
 	for i, test := range equalityTests {
 		t.Run(fmt.Sprintf("Equality tests %d", i), func(t *testing.T) {
-			featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.LogarithmicScaleDown, !test.disableLogarithmicScaleDown)
 			if test.p2 == nil {
 				test.p2 = test.p1
 			}
@@ -869,9 +867,8 @@ func TestSortingActivePodsWithRanks(t *testing.T) {
 		rank int
 	}
 	inequalityTests := []struct {
-		lesser, greater             podWithRank
-		disablePodDeletioncost      bool
-		disableLogarithmicScaleDown bool
+		lesser, greater        podWithRank
+		disablePodDeletioncost bool
 	}{
 		{lesser: podWithRank{unscheduledPod, 1}, greater: podWithRank{scheduledPendingPod, 2}},
 		{lesser: podWithRank{unscheduledPod, 2}, greater: podWithRank{scheduledPendingPod, 1}},
@@ -895,8 +892,7 @@ func TestSortingActivePodsWithRanks(t *testing.T) {
 	for i, test := range inequalityTests {
 		t.Run(fmt.Sprintf("Inequality tests %d", i), func(t *testing.T) {
 			featuregatetesting.SetFeatureGatesDuringTest(t, utilfeature.DefaultFeatureGate, featuregatetesting.FeatureOverrides{
-				features.PodDeletionCost:      !test.disablePodDeletioncost,
-				features.LogarithmicScaleDown: !test.disableLogarithmicScaleDown,
+				features.PodDeletionCost: !test.disablePodDeletioncost,
 			})
 
 			podsWithRanks := ActivePodsWithRanks{

pkg/controller/replicaset/metrics/metrics.go

@@ -28,8 +28,8 @@ var (
 			Subsystem: ReplicaSetControllerSubsystem,
 			Name:      "sorting_deletion_age_ratio",
 			Help: "The ratio of chosen deleted pod's ages to the current youngest pod's age (at the time). Should be <2. " +
-				"The intent of this metric is to measure the rough efficacy of the LogarithmicScaleDown feature gate's effect on " +
-				"the sorting (and deletion) of pods when a replicaset scales down. This only considers Ready pods when calculating and reporting.",
+				"The intent of this metric is to measure the rough efficacy of the sorting (and deletion) of pods when " +
+				"a replicaset scales down. This only considers Ready pods when calculating and reporting.",
 			Buckets:        metrics.ExponentialBuckets(0.25, 2, 6),
 			StabilityLevel: metrics.ALPHA,
 		},

pkg/features/kube_features.go

@@ -604,11 +604,6 @@ const (
 	// Relies on UserNamespacesSupport feature, and thus should follow it when setting defaults.
 	LocalStorageCapacityIsolationFSQuotaMonitoring featuregate.Feature = "LocalStorageCapacityIsolationFSQuotaMonitoring"
 
-	// owner: @damemi
-	//
-	// Enables scaling down replicas via logarithmic comparison of creation/ready timestamps
-	LogarithmicScaleDown featuregate.Feature = "LogarithmicScaleDown"
-
 	// owner: @sanposhiho
 	// kep: https://kep.k8s.io/3633
 	//
@@ -1631,12 +1626,6 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 		{Version: version.MustParse("1.31"), Default: false, PreRelease: featuregate.Beta},
 	},
 
-	LogarithmicScaleDown: {
-		{Version: version.MustParse("1.21"), Default: false, PreRelease: featuregate.Alpha},
-		{Version: version.MustParse("1.22"), Default: true, PreRelease: featuregate.Beta},
-		{Version: version.MustParse("1.31"), Default: true, PreRelease: featuregate.GA, LockToDefault: true},
-	},
-
 	MatchLabelKeysInPodAffinity: {
 		{Version: version.MustParse("1.29"), Default: false, PreRelease: featuregate.Alpha},
 		{Version: version.MustParse("1.31"), Default: true, PreRelease: featuregate.Beta},
@@ -2513,8 +2502,6 @@ var defaultKubernetesFeatureGateDependencies = map[featuregate.Feature][]feature
 
 	LocalStorageCapacityIsolationFSQuotaMonitoring: {},
 
-	LogarithmicScaleDown: {},
-
 	MatchLabelKeysInPodAffinity: {},
 
 	MatchLabelKeysInPodTopologySpread: {},

test/compatibility_lifecycle/reference/feature_list.md

@@ -122,7 +122,6 @@
 | KubeletTracing | :ballot_box_with_check: 1.27+ | :closed_lock_with_key: 1.34+ | 1.25–1.26 | 1.27–1.33 | 1.34– |  |  | [code](https://cs.k8s.io/?q=%5CbKubeletTracing%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/kubernetes) [KEPs](https://cs.k8s.io/?q=%5CbKubeletTracing%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/enhancements) |
 | ListFromCacheSnapshot | :ballot_box_with_check: 1.34+ |  | 1.33 | 1.34– |  |  |  | [code](https://cs.k8s.io/?q=%5CbListFromCacheSnapshot%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/kubernetes) [KEPs](https://cs.k8s.io/?q=%5CbListFromCacheSnapshot%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/enhancements) |
 | LocalStorageCapacityIsolationFSQuotaMonitoring |  |  | 1.15–1.30 | 1.31– |  |  |  | [code](https://cs.k8s.io/?q=%5CbLocalStorageCapacityIsolationFSQuotaMonitoring%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/kubernetes) [KEPs](https://cs.k8s.io/?q=%5CbLocalStorageCapacityIsolationFSQuotaMonitoring%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/enhancements) |
-| LogarithmicScaleDown | :ballot_box_with_check: 1.22+ | :closed_lock_with_key: 1.31+ | 1.21 | 1.22–1.30 | 1.31– |  |  | [code](https://cs.k8s.io/?q=%5CbLogarithmicScaleDown%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/kubernetes) [KEPs](https://cs.k8s.io/?q=%5CbLogarithmicScaleDown%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/enhancements) |
 | ManifestBasedAdmissionControlConfig |  |  | 1.36– |  |  |  |  | [code](https://cs.k8s.io/?q=%5CbManifestBasedAdmissionControlConfig%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/kubernetes) [KEPs](https://cs.k8s.io/?q=%5CbManifestBasedAdmissionControlConfig%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/enhancements) |
 | MatchLabelKeysInPodAffinity | :ballot_box_with_check: 1.31+ | :closed_lock_with_key: 1.33+ | 1.29–1.30 | 1.31–1.32 | 1.33– |  |  | [code](https://cs.k8s.io/?q=%5CbMatchLabelKeysInPodAffinity%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/kubernetes) [KEPs](https://cs.k8s.io/?q=%5CbMatchLabelKeysInPodAffinity%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/enhancements) |
 | MatchLabelKeysInPodTopologySpread | :ballot_box_with_check: 1.27+ |  | 1.25–1.26 | 1.27– |  |  |  | [code](https://cs.k8s.io/?q=%5CbMatchLabelKeysInPodTopologySpread%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/kubernetes) [KEPs](https://cs.k8s.io/?q=%5CbMatchLabelKeysInPodTopologySpread%5Cb&i=nope&files=&excludeFiles=CHANGELOG&repos=kubernetes/enhancements) |

test/compatibility_lifecycle/reference/versioned_feature_list.yaml

@@ -1111,20 +1111,6 @@
     lockToDefault: false
     preRelease: Beta
     version: "1.31"
-- name: LogarithmicScaleDown
-  versionedSpecs:
-  - default: false
-    lockToDefault: false
-    preRelease: Alpha
-    version: "1.21"
-  - default: true
-    lockToDefault: false
-    preRelease: Beta
-    version: "1.22"
-  - default: true
-    lockToDefault: true
-    preRelease: GA
-    version: "1.31"
 - name: LoggingAlphaOptions
   versionedSpecs:
   - default: false

test/integration/replicationcontroller/replicationcontroller_test.go

@@ -30,18 +30,15 @@ import (
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/util/uuid"
 	"k8s.io/apimachinery/pkg/util/wait"
-	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/client-go/informers"
 	clientset "k8s.io/client-go/kubernetes"
 	typedv1 "k8s.io/client-go/kubernetes/typed/core/v1"
 	restclient "k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/util/retry"
-	featuregatetesting "k8s.io/component-base/featuregate/testing"
 	kubeapiservertesting "k8s.io/kubernetes/cmd/kube-apiserver/app/testing"
 	podutil "k8s.io/kubernetes/pkg/api/v1/pod"
 	"k8s.io/kubernetes/pkg/controller/replication"
-	"k8s.io/kubernetes/pkg/features"
 	"k8s.io/kubernetes/test/integration/framework"
 	"k8s.io/kubernetes/test/utils/ktesting"
 	"k8s.io/utils/ptr"
@@ -503,7 +500,6 @@ func TestSpecReplicasChange(t *testing.T) {
 }
 
 func TestLogarithmicScaleDown(t *testing.T) {
-	featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.LogarithmicScaleDown, true)
 	tCtx, closeFn, rm, informers, c := rmSetup(t)
 	defer closeFn()
 	ns := framework.CreateNamespaceOrDie(c, "test-spec-replicas-change", t)