Merge pull request kubernetes#128629 from liggitt/revert-spreadkubeletload

Revert "Add random interval to nodeStatusReport interval every time after an actual node status change

Author: k8s-ci-robot

pkg/kubelet/kubelet.go

@@ -1240,12 +1240,6 @@ type Kubelet struct {
 	// status to master. It is only used when node lease feature is enabled.
 	nodeStatusReportFrequency time.Duration
 
-	// delayAfterNodeStatusChange is the one-time random duration that we add to the next node status report interval
-	// every time when there's an actual node status change. But all future node status update that is not caused by
-	// real status change will stick with nodeStatusReportFrequency. The random duration is a uniform distribution over
-	// [-0.5*nodeStatusReportFrequency, 0.5*nodeStatusReportFrequency]
-	delayAfterNodeStatusChange time.Duration
-
 	// lastStatusReportTime is the time when node status was last reported.
 	lastStatusReportTime time.Time
 

pkg/kubelet/kubelet_node_status.go

@@ -19,7 +19,6 @@ package kubelet
 import (
 	"context"
 	"fmt"
-	"math/rand"
 	"net"
 	goruntime "runtime"
 	"sort"
@@ -580,42 +579,20 @@ func (kl *Kubelet) tryUpdateNodeStatus(ctx context.Context, tryNumber int) error
 	}
 
 	node, changed := kl.updateNode(ctx, originalNode)
-	// no need to update the status yet
-	if !changed && !kl.isUpdateStatusPeriodExperid() {
+	shouldPatchNodeStatus := changed || kl.clock.Since(kl.lastStatusReportTime) >= kl.nodeStatusReportFrequency
+
+	if !shouldPatchNodeStatus {
 		kl.markVolumesFromNode(node)
 		return nil
 	}
 
-	// We need to update the node status, if this is caused by a node change we want to calculate a new
-	// random delay so we avoid all the nodes to reach the apiserver at the same time. If the update is not related
-	// to a node change, because we run over the period, we reset the random delay so the node keeps updating
-	// its status at the same cadence
-	if changed {
-		kl.delayAfterNodeStatusChange = kl.calculateDelay()
-	} else {
-		kl.delayAfterNodeStatusChange = 0
-	}
 	updatedNode, err := kl.patchNodeStatus(originalNode, node)
 	if err == nil {
 		kl.markVolumesFromNode(updatedNode)
 	}
 	return err
 }
 
-func (kl *Kubelet) isUpdateStatusPeriodExperid() bool {
-	if kl.lastStatusReportTime.IsZero() {
-		return false
-	}
-	if kl.clock.Since(kl.lastStatusReportTime) >= kl.nodeStatusReportFrequency+kl.delayAfterNodeStatusChange {
-		return true
-	}
-	return false
-}
-
-func (kl *Kubelet) calculateDelay() time.Duration {
-	return time.Duration(float64(kl.nodeStatusReportFrequency) * (-0.5 + rand.Float64()))
-}
-
 // updateNode creates a copy of originalNode and runs update logic on it.
 // It returns the updated node object and a bool indicating if anything has been changed.
 func (kl *Kubelet) updateNode(ctx context.Context, originalNode *v1.Node) (*v1.Node, bool) {

pkg/kubelet/kubelet_node_status_test.go

@@ -3088,67 +3088,3 @@ func TestUpdateNodeAddresses(t *testing.T) {
 		})
 	}
 }
-
-func TestIsUpdateStatusPeriodExperid(t *testing.T) {
-	testcases := []struct {
-		name                       string
-		lastStatusReportTime       time.Time
-		delayAfterNodeStatusChange time.Duration
-		expectExpired              bool
-	}{
-		{
-			name:                       "no status update before and no delay",
-			lastStatusReportTime:       time.Time{},
-			delayAfterNodeStatusChange: 0,
-			expectExpired:              false,
-		},
-		{
-			name:                       "no status update before and existing delay",
-			lastStatusReportTime:       time.Time{},
-			delayAfterNodeStatusChange: 30 * time.Second,
-			expectExpired:              false,
-		},
-		{
-			name:                       "not expired and no delay",
-			lastStatusReportTime:       time.Now().Add(-4 * time.Minute),
-			delayAfterNodeStatusChange: 0,
-			expectExpired:              false,
-		},
-		{
-			name:                       "not expired",
-			lastStatusReportTime:       time.Now().Add(-5 * time.Minute),
-			delayAfterNodeStatusChange: time.Minute,
-			expectExpired:              false,
-		},
-		{
-			name:                       "expired",
-			lastStatusReportTime:       time.Now().Add(-4 * time.Minute),
-			delayAfterNodeStatusChange: -2 * time.Minute,
-			expectExpired:              true,
-		},
-	}
-
-	testKubelet := newTestKubelet(t, false /* controllerAttachDetachEnabled */)
-	defer testKubelet.Cleanup()
-	kubelet := testKubelet.kubelet
-	kubelet.nodeStatusReportFrequency = 5 * time.Minute
-
-	for _, tc := range testcases {
-		kubelet.lastStatusReportTime = tc.lastStatusReportTime
-		kubelet.delayAfterNodeStatusChange = tc.delayAfterNodeStatusChange
-		expired := kubelet.isUpdateStatusPeriodExperid()
-		assert.Equal(t, tc.expectExpired, expired, tc.name)
-	}
-}
-
-func TestCalculateDelay(t *testing.T) {
-	testKubelet := newTestKubelet(t, false /* controllerAttachDetachEnabled */)
-	defer testKubelet.Cleanup()
-	kubelet := testKubelet.kubelet
-	kubelet.nodeStatusReportFrequency = 5 * time.Minute
-
-	for i := 0; i < 100; i++ {
-		randomDelay := kubelet.calculateDelay()
-		assert.LessOrEqual(t, randomDelay.Abs(), kubelet.nodeStatusReportFrequency/2)
-	}
-}