Fix an e2e flake on updating node status

test/e2e/scheduling/BUILD

@@ -31,8 +31,10 @@ go_library(
         "//staging/src/k8s.io/apimachinery/pkg/fields:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/labels:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/intstr:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/strategicpatch:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/uuid:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/version:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/wait:go_default_library",

test/e2e/scheduling/preemption.go

@@ -18,6 +18,7 @@ package scheduling
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"strings"
 	"sync/atomic"
@@ -30,7 +31,9 @@ import (
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apimachinery/pkg/util/strategicpatch"
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apimachinery/pkg/watch"
 	clientset "k8s.io/client-go/kubernetes"
@@ -40,7 +43,6 @@ import (
 	e2enode "k8s.io/kubernetes/test/e2e/framework/node"
 	e2epod "k8s.io/kubernetes/test/e2e/framework/pod"
 	e2ereplicaset "k8s.io/kubernetes/test/e2e/framework/replicaset"
-	e2eskipper "k8s.io/kubernetes/test/e2e/framework/skipper"
 
 	"github.com/onsi/ginkgo"
 	"github.com/onsi/gomega"
@@ -77,8 +79,10 @@ var _ = SIGDescribe("SchedulerPreemption [Serial]", func() {
 			cs.SchedulingV1().PriorityClasses().Delete(context.TODO(), pair.name, *metav1.NewDeleteOptions(0))
 		}
 		for _, node := range nodeList.Items {
-			delete(node.Status.Capacity, testExtendedResource)
+			nodeCopy := node.DeepCopy()
-			cs.CoreV1().Nodes().UpdateStatus(context.TODO(), &node, metav1.UpdateOptions{})
+			delete(nodeCopy.Status.Capacity, testExtendedResource)
+			err := patchNode(cs, &node, nodeCopy)
+			framework.ExpectNoError(err)
 		}
 	})
 
@@ -119,8 +123,9 @@ var _ = SIGDescribe("SchedulerPreemption [Serial]", func() {
 		// Now create victim pods on each of the node with lower priority
 		for i, node := range nodeList.Items {
 			// Update each node to advertise 3 available extended resources
-			node.Status.Capacity[testExtendedResource] = resource.MustParse("3")
+			nodeCopy := node.DeepCopy()
-			node, err := cs.CoreV1().Nodes().UpdateStatus(context.TODO(), &node, metav1.UpdateOptions{})
+			nodeCopy.Status.Capacity[testExtendedResource] = resource.MustParse("3")
+			err := patchNode(cs, &node, nodeCopy)
 			framework.ExpectNoError(err)
 
 			// Request 2 of the available resources for the victim pods
@@ -204,8 +209,9 @@ var _ = SIGDescribe("SchedulerPreemption [Serial]", func() {
 		pods := make([]*v1.Pod, 0, len(nodeList.Items))
 		for i, node := range nodeList.Items {
 			// Update each node to advertise 3 available extended resources
-			node.Status.Capacity[testExtendedResource] = resource.MustParse("3")
+			nodeCopy := node.DeepCopy()
-			node, err := cs.CoreV1().Nodes().UpdateStatus(context.TODO(), &node, metav1.UpdateOptions{})
+			nodeCopy.Status.Capacity[testExtendedResource] = resource.MustParse("3")
+			err := patchNode(cs, &node, nodeCopy)
 			framework.ExpectNoError(err)
 
 			// Request 2 of the available resources for the victim pods
@@ -241,7 +247,7 @@ var _ = SIGDescribe("SchedulerPreemption [Serial]", func() {
 			framework.Logf("Created pod: %v", pods[i].Name)
 		}
 		if len(pods) < 2 {
-			e2eskipper.Skipf("We need at least two pods to be created but" +
+			framework.Failf("We need at least two pods to be created but" +
 				"all nodes are already heavily utilized, so preemption tests cannot be run")
 		}
 		ginkgo.By("Wait for pods to be scheduled.")
@@ -305,12 +311,10 @@ var _ = SIGDescribe("SchedulerPreemption [Serial]", func() {
 				node, err := cs.CoreV1().Nodes().Get(context.TODO(), nodeName, metav1.GetOptions{})
 				framework.ExpectNoError(err)
 				// update Node API object with a fake resource
-				nodeCopy := node.DeepCopy()
-				// force it to update
-				nodeCopy.ResourceVersion = "0"
 				ginkgo.By(fmt.Sprintf("Apply 10 fake resource to node %v.", node.Name))
+				nodeCopy := node.DeepCopy()
 				nodeCopy.Status.Capacity[fakeRes] = resource.MustParse("10")
-				node, err = cs.CoreV1().Nodes().UpdateStatus(context.TODO(), nodeCopy, metav1.UpdateOptions{})
+				err = patchNode(cs, node, nodeCopy)
 				framework.ExpectNoError(err)
 				nodes = append(nodes, node)
 			}
@@ -321,10 +325,8 @@ var _ = SIGDescribe("SchedulerPreemption [Serial]", func() {
 			}
 			for _, node := range nodes {
 				nodeCopy := node.DeepCopy()
-				// force it to update
-				nodeCopy.ResourceVersion = "0"
 				delete(nodeCopy.Status.Capacity, fakeRes)
-				_, err := cs.CoreV1().Nodes().UpdateStatus(context.TODO(), nodeCopy, metav1.UpdateOptions{})
+				err := patchNode(cs, node, nodeCopy)
 				framework.ExpectNoError(err)
 			}
 		})
@@ -470,10 +472,8 @@ var _ = SIGDescribe("SchedulerPreemption [Serial]", func() {
 
 			if node != nil {
 				nodeCopy := node.DeepCopy()
-				// force it to update
-				nodeCopy.ResourceVersion = "0"
 				delete(nodeCopy.Status.Capacity, fakecpu)
-				_, err := cs.CoreV1().Nodes().UpdateStatus(context.TODO(), nodeCopy, metav1.UpdateOptions{})
+				err := patchNode(cs, node, nodeCopy)
 				framework.ExpectNoError(err)
 			}
 			for _, pair := range priorityPairs {
@@ -504,10 +504,8 @@ var _ = SIGDescribe("SchedulerPreemption [Serial]", func() {
 
 			// update Node API object with a fake resource
 			nodeCopy := node.DeepCopy()
-			// force it to update
-			nodeCopy.ResourceVersion = "0"
 			nodeCopy.Status.Capacity[fakecpu] = resource.MustParse("1000")
-			node, err = cs.CoreV1().Nodes().UpdateStatus(context.TODO(), nodeCopy, metav1.UpdateOptions{})
+			err = patchNode(cs, node, nodeCopy)
 			framework.ExpectNoError(err)
 
 			// create four PriorityClass: p1, p2, p3, p4
@@ -737,3 +735,21 @@ func waitForPreemptingWithTimeout(f *framework.Framework, pod *v1.Pod, timeout t
 	})
 	framework.ExpectNoError(err, "pod %v/%v failed to preempt other pods", pod.Namespace, pod.Name)
 }
+
+func patchNode(client clientset.Interface, old *v1.Node, new *v1.Node) error {
+	oldData, err := json.Marshal(old)
+	if err != nil {
+		return err
+	}
+
+	newData, err := json.Marshal(new)
+	if err != nil {
+		return err
+	}
+	patchBytes, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, &v1.Node{})
+	if err != nil {
+		return fmt.Errorf("failed to create merge patch for node %q: %v", old.Name, err)
+	}
+	_, err = client.CoreV1().Nodes().Patch(context.TODO(), old.Name, types.StrategicMergePatchType, patchBytes, metav1.PatchOptions{}, "status")
+	return err
+}