Merge pull request #86498 from Huang-Wei/deprecate-failedPredicateMap

Cleanup failedPredicateMap from generic_scheduler.go

pkg/scheduler/core/generic_scheduler.go

@@ -66,15 +66,10 @@ const (
 	minFeasibleNodesPercentageToFind = 5
 )
 
-// FailedPredicateMap declares a map[string][]algorithm.PredicateFailureReason type.
-type FailedPredicateMap map[string][]predicates.PredicateFailureReason
-
 // FitError describes a fit error of a pod.
 type FitError struct {
 	Pod                   *v1.Pod
 	NumAllNodes           int
-	// TODO(Huang-Wei): remove 'FailedPredicates'
-	FailedPredicates      FailedPredicateMap
 	FilteredNodesStatuses framework.NodeToStatusMap
 }
 
@@ -89,12 +84,6 @@ const (
 // Error returns detailed information of why the pod failed to fit on each node
 func (f *FitError) Error() string {
 	reasons := make(map[string]int)
-	for _, predicates := range f.FailedPredicates {
-		for _, pred := range predicates {
-			reasons[pred.GetReason()]++
-		}
-	}
-
 	for _, status := range f.FilteredNodesStatuses {
 		for _, reason := range status.Reasons() {
 			reasons[reason]++
@@ -102,7 +91,7 @@ func (f *FitError) Error() string {
 	}
 
 	sortReasonsHistogram := func() []string {
-		reasonStrings := []string{}
+		var reasonStrings []string
 		for k, v := range reasons {
 			reasonStrings = append(reasonStrings, fmt.Sprintf("%v %v", v, k))
 		}
@@ -209,7 +198,7 @@ func (g *genericScheduler) Schedule(ctx context.Context, state *framework.CycleS
 	trace.Step("Running prefilter plugins done")
 
 	startPredicateEvalTime := time.Now()
-	filteredNodes, failedPredicateMap, filteredNodesStatuses, err := g.findNodesThatFit(ctx, state, pod)
+	filteredNodes, filteredNodesStatuses, err := g.findNodesThatFit(ctx, state, pod)
 	if err != nil {
 		return result, err
 	}
@@ -225,7 +214,6 @@ func (g *genericScheduler) Schedule(ctx context.Context, state *framework.CycleS
 		return result, &FitError{
 			Pod:                   pod,
 			NumAllNodes:           len(g.nodeInfoSnapshot.NodeInfoList),
-			FailedPredicates:      failedPredicateMap,
 			FilteredNodesStatuses: filteredNodesStatuses,
 		}
 	}
@@ -242,7 +230,7 @@ func (g *genericScheduler) Schedule(ctx context.Context, state *framework.CycleS
 		metrics.DeprecatedSchedulingAlgorithmPriorityEvaluationDuration.Observe(metrics.SinceInMicroseconds(startPriorityEvalTime))
 		return ScheduleResult{
 			SuggestedHost:  filteredNodes[0].Name,
-			EvaluatedNodes: 1 + len(failedPredicateMap) + len(filteredNodesStatuses),
+			EvaluatedNodes: 1 + len(filteredNodesStatuses),
 			FeasibleNodes:  1,
 		}, nil
 	}
@@ -263,7 +251,7 @@ func (g *genericScheduler) Schedule(ctx context.Context, state *framework.CycleS
 
 	return ScheduleResult{
 		SuggestedHost:  host,
-		EvaluatedNodes: len(filteredNodes) + len(failedPredicateMap) + len(filteredNodesStatuses),
+		EvaluatedNodes: len(filteredNodes) + len(filteredNodesStatuses),
 		FeasibleNodes:  len(filteredNodes),
 	}, err
 }
@@ -470,10 +458,8 @@ func (g *genericScheduler) numFeasibleNodesToFind(numAllNodes int32) (numNodes i
 
 // Filters the nodes to find the ones that fit based on the given predicate functions
 // Each node is passed through the predicate functions to determine if it is a fit
-// TODO(Huang-Wei): remove 'FailedPredicateMap' from the return parameters.
-func (g *genericScheduler) findNodesThatFit(ctx context.Context, state *framework.CycleState, pod *v1.Pod) ([]*v1.Node, FailedPredicateMap, framework.NodeToStatusMap, error) {
+func (g *genericScheduler) findNodesThatFit(ctx context.Context, state *framework.CycleState, pod *v1.Pod) ([]*v1.Node, framework.NodeToStatusMap, error) {
 	var filtered []*v1.Node
-	failedPredicateMap := FailedPredicateMap{}
 	filteredNodesStatuses := framework.NodeToStatusMap{}
 
 	if !g.framework.HasFilterPlugins() {
@@ -496,7 +482,7 @@ func (g *genericScheduler) findNodesThatFit(ctx context.Context, state *framewor
 			// We check the nodes starting from where we left off in the previous scheduling cycle,
 			// this is to make sure all nodes have the same chance of being examined across pods.
 			nodeInfo := g.nodeInfoSnapshot.NodeInfoList[(g.nextStartNodeIndex+i)%allNodes]
-			fits, _, status, err := g.podFitsOnNode(ctx, state, pod, nodeInfo)
+			fits, status, err := g.podFitsOnNode(ctx, state, pod, nodeInfo)
 			if err != nil {
 				errCh.SendErrorWithCancel(err, cancel)
 				return
@@ -521,12 +507,12 @@ func (g *genericScheduler) findNodesThatFit(ctx context.Context, state *framewor
 		// Stops searching for more nodes once the configured number of feasible nodes
 		// are found.
 		workqueue.ParallelizeUntil(ctx, 16, allNodes, checkNode)
-		processedNodes := int(filteredLen) + len(filteredNodesStatuses) + len(failedPredicateMap)
+		processedNodes := int(filteredLen) + len(filteredNodesStatuses)
 		g.nextStartNodeIndex = (g.nextStartNodeIndex + processedNodes) % allNodes
 
 		filtered = filtered[:filteredLen]
 		if err := errCh.ReceiveError(); err != nil {
-			return []*v1.Node{}, FailedPredicateMap{}, framework.NodeToStatusMap{}, err
+			return []*v1.Node{}, framework.NodeToStatusMap{}, err
 		}
 	}
 
@@ -543,15 +529,15 @@ func (g *genericScheduler) findNodesThatFit(ctx context.Context, state *framewor
 					continue
 				}
 
-				return []*v1.Node{}, FailedPredicateMap{}, framework.NodeToStatusMap{}, err
+				return []*v1.Node{}, framework.NodeToStatusMap{}, err
 			}
 
-			// TODO(Huang-Wei): refactor this to fill 'filteredNodesStatuses' instead of 'failedPredicateMap'.
 			for failedNodeName, failedMsg := range failedMap {
-				if _, found := failedPredicateMap[failedNodeName]; !found {
-					failedPredicateMap[failedNodeName] = []predicates.PredicateFailureReason{}
+				if _, found := filteredNodesStatuses[failedNodeName]; !found {
+					filteredNodesStatuses[failedNodeName] = framework.NewStatus(framework.Unschedulable, failedMsg)
+				} else {
+					filteredNodesStatuses[failedNodeName].AppendReason(failedMsg)
 				}
-				failedPredicateMap[failedNodeName] = append(failedPredicateMap[failedNodeName], predicates.NewPredicateFailureError(extender.Name(), failedMsg))
 			}
 			filtered = filteredList
 			if len(filtered) == 0 {
@@ -559,7 +545,7 @@ func (g *genericScheduler) findNodesThatFit(ctx context.Context, state *framewor
 			}
 		}
 	}
-	return filtered, failedPredicateMap, filteredNodesStatuses, nil
+	return filtered, filteredNodesStatuses, nil
 }
 
 // addNominatedPods adds pods with equal or greater priority which are nominated
@@ -606,8 +592,7 @@ func (g *genericScheduler) podFitsOnNode(
 	state *framework.CycleState,
 	pod *v1.Pod,
 	info *schedulernodeinfo.NodeInfo,
-) (bool, []predicates.PredicateFailureReason, *framework.Status, error) {
-	var failedPredicates []predicates.PredicateFailureReason
+) (bool, *framework.Status, error) {
 	var status *framework.Status
 
 	podsAdded := false
@@ -636,19 +621,19 @@ func (g *genericScheduler) podFitsOnNode(
 			var err error
 			podsAdded, stateToUse, nodeInfoToUse, err = g.addNominatedPods(ctx, pod, state, info)
 			if err != nil {
-				return false, []predicates.PredicateFailureReason{}, nil, err
+				return false, nil, err
 			}
-		} else if !podsAdded || len(failedPredicates) != 0 || !status.IsSuccess() {
+		} else if !podsAdded || !status.IsSuccess() {
 			break
 		}
 
 		status = g.framework.RunFilterPlugins(ctx, stateToUse, pod, nodeInfoToUse)
 		if !status.IsSuccess() && !status.IsUnschedulable() {
-			return false, failedPredicates, status, status.AsError()
+			return false, status, status.AsError()
 		}
 	}
 
-	return len(failedPredicates) == 0 && status.IsSuccess(), failedPredicates, status, nil
+	return status.IsSuccess(), status, nil
 }
 
 // prioritizeNodes prioritizes the nodes by running the score plugins,
@@ -1011,7 +996,7 @@ func (g *genericScheduler) selectVictimsOnNode(
 	// inter-pod affinity to one or more victims, but we have decided not to
 	// support this case for performance reasons. Having affinity to lower
 	// priority pods is not a recommended configuration anyway.
-	if fits, _, _, err := g.podFitsOnNode(ctx, state, pod, nodeInfo); !fits {
+	if fits, _, err := g.podFitsOnNode(ctx, state, pod, nodeInfo); !fits {
 		if err != nil {
 			klog.Warningf("Encountered error while selecting victims on node %v: %v", nodeInfo.Node().Name, err)
 		}
@@ -1029,7 +1014,7 @@ func (g *genericScheduler) selectVictimsOnNode(
 		if err := addPod(p); err != nil {
 			return false, err
 		}
-		fits, _, _, _ := g.podFitsOnNode(ctx, state, pod, nodeInfo)
+		fits, _, _ := g.podFitsOnNode(ctx, state, pod, nodeInfo)
 		if !fits {
 			if err := removePod(p); err != nil {
 				return false, err
@@ -1060,23 +1045,16 @@ func (g *genericScheduler) selectVictimsOnNode(
 // nodesWherePreemptionMightHelp returns a list of nodes with failed predicates
 // that may be satisfied by removing pods from the node.
 func nodesWherePreemptionMightHelp(nodeNameToInfo map[string]*schedulernodeinfo.NodeInfo, fitErr *FitError) []*v1.Node {
-	potentialNodes := []*v1.Node{}
+	var potentialNodes []*v1.Node
 	for name, node := range nodeNameToInfo {
+		// We reply on the status by each plugin - 'Unschedulable' or 'UnschedulableAndUnresolvable'
+		// to determine whether preemption may help or not on the node.
 		if fitErr.FilteredNodesStatuses[name].Code() == framework.UnschedulableAndUnresolvable {
 			continue
 		}
-		failedPredicates := fitErr.FailedPredicates[name]
-
-		// If we assume that scheduler looks at all nodes and populates the failedPredicateMap
-		// (which is the case today), the !found case should never happen, but we'd prefer
-		// to rely less on such assumptions in the code when checking does not impose
-		// significant overhead.
-		// Also, we currently assume all failures returned by extender as resolvable.
-		if !predicates.UnresolvablePredicateExists(failedPredicates) {
 		klog.V(3).Infof("Node %v is a potential node for preemption.", name)
 		potentialNodes = append(potentialNodes, node.Node())
 	}
-	}
 	return potentialNodes
 }
 

pkg/scheduler/core/generic_scheduler_test.go

@@ -389,7 +389,6 @@ func TestGenericScheduler(t *testing.T) {
 			wErr: &FitError{
 				Pod:         &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "2", UID: types.UID("2")}},
 				NumAllNodes: 2,
-				FailedPredicates: FailedPredicateMap{},
 				FilteredNodesStatuses: framework.NodeToStatusMap{
 					"machine1": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrFakePredicate.GetReason()),
 					"machine2": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrFakePredicate.GetReason()),
@@ -463,7 +462,6 @@ func TestGenericScheduler(t *testing.T) {
 			wErr: &FitError{
 				Pod:         &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "2", UID: types.UID("2")}},
 				NumAllNodes: 3,
-				FailedPredicates: FailedPredicateMap{},
 				FilteredNodesStatuses: framework.NodeToStatusMap{
 					"3": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrFakePredicate.GetReason()),
 					"2": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrFakePredicate.GetReason()),
@@ -494,7 +492,6 @@ func TestGenericScheduler(t *testing.T) {
 			wErr: &FitError{
 				Pod:         &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "2", UID: types.UID("2")}},
 				NumAllNodes: 2,
-				FailedPredicates: FailedPredicateMap{},
 				FilteredNodesStatuses: framework.NodeToStatusMap{
 					"1": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrFakePredicate.GetReason()),
 					"2": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrFakePredicate.GetReason()),
@@ -709,7 +706,6 @@ func TestGenericScheduler(t *testing.T) {
 			wErr: &FitError{
 				Pod:         &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "test-filter", UID: types.UID("test-filter")}},
 				NumAllNodes: 1,
-				FailedPredicates: FailedPredicateMap{},
 				FilteredNodesStatuses: framework.NodeToStatusMap{
 					"3": framework.NewStatus(framework.Unschedulable, "injecting failure for pod test-filter"),
 				},
@@ -730,7 +726,6 @@ func TestGenericScheduler(t *testing.T) {
 			wErr: &FitError{
 				Pod:         &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "test-filter", UID: types.UID("test-filter")}},
 				NumAllNodes: 1,
-				FailedPredicates: FailedPredicateMap{},
 				FilteredNodesStatuses: framework.NodeToStatusMap{
 					"3": framework.NewStatus(framework.UnschedulableAndUnresolvable, "injecting failure for pod test-filter"),
 				},
@@ -852,7 +847,7 @@ func TestFindFitAllError(t *testing.T) {
 		st.RegisterFilterPlugin("MatchFilter", NewMatchFilterPlugin),
 	)
 
-	_, _, nodeToStatusMap, err := scheduler.findNodesThatFit(context.Background(), framework.NewCycleState(), &v1.Pod{})
+	_, nodeToStatusMap, err := scheduler.findNodesThatFit(context.Background(), framework.NewCycleState(), &v1.Pod{})
 
 	if err != nil {
 		t.Errorf("unexpected error: %v", err)
@@ -886,7 +881,7 @@ func TestFindFitSomeError(t *testing.T) {
 	)
 
 	pod := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "1", UID: types.UID("1")}}
-	_, _, nodeToStatusMap, err := scheduler.findNodesThatFit(context.Background(), framework.NewCycleState(), pod)
+	_, nodeToStatusMap, err := scheduler.findNodesThatFit(context.Background(), framework.NewCycleState(), pod)
 
 	if err != nil {
 		t.Errorf("unexpected error: %v", err)
@@ -969,7 +964,7 @@ func TestFindFitPredicateCallCounts(t *testing.T) {
 		cache.UpdateNodeInfoSnapshot(scheduler.nodeInfoSnapshot)
 		queue.UpdateNominatedPodForNode(&v1.Pod{ObjectMeta: metav1.ObjectMeta{UID: types.UID("nominated")}, Spec: v1.PodSpec{Priority: &midPriority}}, "1")
 
-		_, _, _, err := scheduler.findNodesThatFit(context.Background(), framework.NewCycleState(), test.pod)
+		_, _, err := scheduler.findNodesThatFit(context.Background(), framework.NewCycleState(), test.pod)
 
 		if err != nil {
 			t.Errorf("unexpected error: %v", err)
@@ -1003,10 +998,10 @@ func TestHumanReadableFitError(t *testing.T) {
 	err := &FitError{
 		Pod:         &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "2", UID: types.UID("2")}},
 		NumAllNodes: 3,
-		FailedPredicates: FailedPredicateMap{
-			"1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeUnderMemoryPressure},
-			"2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeUnderDiskPressure},
-			"3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeUnderDiskPressure},
+		FilteredNodesStatuses: framework.NodeToStatusMap{
+			"1": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrNodeUnderMemoryPressure.GetReason()),
+			"2": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrNodeUnderDiskPressure.GetReason()),
+			"3": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrNodeUnderDiskPressure.GetReason()),
 		},
 	}
 	if strings.Contains(err.Error(), "0/3 nodes are available") {
@@ -1884,94 +1879,91 @@ func TestNodesWherePreemptionMightHelp(t *testing.T) {
 
 	tests := []struct {
 		name          string
-		failedPredMap FailedPredicateMap
 		nodesStatuses framework.NodeToStatusMap
 		expected      map[string]bool // set of expected node names. Value is ignored.
 	}{
 		{
 			name: "No node should be attempted",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeSelectorNotMatch},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodNotMatchHostName},
-				"machine3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrTaintsTolerationsNotMatch},
-				"machine4": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeLabelPresenceViolated},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeSelectorNotMatch.GetReason()),
+				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrPodNotMatchHostName.GetReason()),
+				"machine3": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrTaintsTolerationsNotMatch.GetReason()),
+				"machine4": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeLabelPresenceViolated.GetReason()),
 			},
 			expected: map[string]bool{},
 		},
 		{
 			name: "ErrPodAffinityNotMatch should be tried as it indicates that the pod is unschedulable due to inter-pod affinity or anti-affinity",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodAffinityNotMatch},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodNotMatchHostName},
-				"machine3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeUnschedulable},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrPodAffinityNotMatch.GetReason()),
+				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrPodNotMatchHostName.GetReason()),
+				"machine3": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeUnschedulable.GetReason()),
 			},
 			expected: map[string]bool{"machine1": true, "machine4": true},
 		},
 		{
 			name: "pod with both pod affinity and anti-affinity should be tried",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodAffinityNotMatch},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodNotMatchHostName},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrPodAffinityNotMatch.GetReason()),
+				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrPodNotMatchHostName.GetReason()),
 			},
 			expected: map[string]bool{"machine1": true, "machine3": true, "machine4": true},
 		},
 		{
 			name: "ErrPodAffinityRulesNotMatch should not be tried as it indicates that the pod is unschedulable due to inter-pod affinity, but ErrPodAffinityNotMatch should be tried as it indicates that the pod is unschedulable due to inter-pod affinity or anti-affinity",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodAffinityRulesNotMatch},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodAffinityNotMatch},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrPodAffinityRulesNotMatch.GetReason()),
+				"machine2": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrPodAffinityNotMatch.GetReason()),
 			},
 			expected: map[string]bool{"machine2": true, "machine3": true, "machine4": true},
 		},
 		{
 			name: "Mix of failed predicates works fine",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeSelectorNotMatch, algorithmpredicates.ErrNodeUnderDiskPressure, algorithmpredicates.NewInsufficientResourceError(v1.ResourceMemory, 1000, 500, 300)},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodNotMatchHostName, algorithmpredicates.ErrDiskConflict},
-				"machine3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.NewInsufficientResourceError(v1.ResourceMemory, 1000, 600, 400)},
-				"machine4": []algorithmpredicates.PredicateFailureReason{},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeUnderDiskPressure.GetReason()),
+				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrDiskConflict.GetReason()),
+				"machine3": framework.NewStatus(framework.Unschedulable, algorithmpredicates.NewInsufficientResourceError(v1.ResourceMemory, 1000, 600, 400).GetReason()),
 			},
 			expected: map[string]bool{"machine3": true, "machine4": true},
 		},
 		{
 			name: "Node condition errors should be considered unresolvable",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeUnderDiskPressure},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeUnderPIDPressure},
-				"machine3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeUnderMemoryPressure},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeUnderDiskPressure.GetReason()),
+				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeUnderPIDPressure.GetReason()),
+				"machine3": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeUnderMemoryPressure.GetReason()),
 			},
 			expected: map[string]bool{"machine4": true},
 		},
 		{
 			name: "Node condition errors and ErrNodeUnknownCondition should be considered unresolvable",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeNotReady},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeNetworkUnavailable},
-				"machine3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrNodeUnknownCondition},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeNotReady.GetReason()),
+				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeNetworkUnavailable.GetReason()),
+				"machine3": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrNodeUnknownCondition.GetReason()),
 			},
 			expected: map[string]bool{"machine4": true},
 		},
 		{
 			name: "ErrVolume... errors should not be tried as it indicates that the pod is unschedulable due to no matching volumes for pod on node",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrVolumeZoneConflict},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrVolumeNodeConflict},
-				"machine3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrVolumeBindConflict},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrVolumeZoneConflict.GetReason()),
+				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrVolumeNodeConflict.GetReason()),
+				"machine3": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrVolumeBindConflict.GetReason()),
 			},
 			expected: map[string]bool{"machine4": true},
 		},
 		{
 			name: "ErrTopologySpreadConstraintsNotMatch should be tried as it indicates that the pod is unschedulable due to topology spread constraints",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrTopologySpreadConstraintsNotMatch},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodNotMatchHostName},
-				"machine3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrTopologySpreadConstraintsNotMatch},
+			nodesStatuses: framework.NodeToStatusMap{
+				"machine1": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrTopologySpreadConstraintsNotMatch.GetReason()),
+				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, algorithmpredicates.ErrPodNotMatchHostName.GetReason()),
+				"machine3": framework.NewStatus(framework.Unschedulable, algorithmpredicates.ErrTopologySpreadConstraintsNotMatch.GetReason()),
 			},
 			expected: map[string]bool{"machine1": true, "machine3": true, "machine4": true},
 		},
 		{
 			name: "UnschedulableAndUnresolvable status should be skipped but Unschedulable should be tried",
-			failedPredMap: FailedPredicateMap{},
 			nodesStatuses: framework.NodeToStatusMap{
 				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
 				"machine3": framework.NewStatus(framework.Unschedulable, ""),
@@ -1979,28 +1971,11 @@ func TestNodesWherePreemptionMightHelp(t *testing.T) {
 			},
 			expected: map[string]bool{"machine1": true, "machine3": true},
 		},
-		{
-			name: "Failed predicates and statuses should be evaluated",
-			failedPredMap: FailedPredicateMap{
-				"machine1": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodAffinityNotMatch},
-				"machine2": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodAffinityNotMatch},
-				"machine3": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodNotMatchHostName},
-				"machine4": []algorithmpredicates.PredicateFailureReason{algorithmpredicates.ErrPodNotMatchHostName},
-			},
-			nodesStatuses: framework.NodeToStatusMap{
-				"machine1": framework.NewStatus(framework.Unschedulable, ""),
-				"machine2": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
-				"machine3": framework.NewStatus(framework.Unschedulable, ""),
-				"machine4": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
-			},
-			expected: map[string]bool{"machine1": true},
-		},
 	}
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			fitErr := FitError{
-				FailedPredicates:      test.failedPredMap,
 				FilteredNodesStatuses: test.nodesStatuses,
 			}
 			nodes := nodesWherePreemptionMightHelp(nodeinfosnapshot.CreateNodeInfoMap(nil, makeNodeList(nodeNames)), &fitErr)
@@ -2494,7 +2469,7 @@ func TestFairEvaluationForNodes(t *testing.T) {
 
 	// Iterating over all nodes more than twice
 	for i := 0; i < 2*(numAllNodes/nodesToFind+1); i++ {
-		nodesThatFit, _, _, err := g.findNodesThatFit(context.Background(), framework.NewCycleState(), &v1.Pod{})
+		nodesThatFit, _, err := g.findNodesThatFit(context.Background(), framework.NewCycleState(), &v1.Pod{})
 		if err != nil {
 			t.Errorf("unexpected error: %v", err)
 		}

pkg/scheduler/framework/v1alpha1/interface.go

@@ -122,6 +122,11 @@ func (s *Status) Reasons() []string {
 	return s.reasons
 }
 
+// AppendReason appends given reason to the Status.
+func (s *Status) AppendReason(reason string) {
+	s.reasons = append(s.reasons, reason)
+}
+
 // IsSuccess returns true if and only if "Status" is nil or Code is "Success".
 func (s *Status) IsSuccess() bool {
 	return s.Code() == Success

pkg/scheduler/scheduler_test.go

@@ -143,10 +143,6 @@ func podWithResources(id, desiredHost string, limits v1.ResourceList, requests v
 	return pod
 }
 
-func PredicateOne(pod *v1.Pod, meta predicates.Metadata, nodeInfo *schedulernodeinfo.NodeInfo) (bool, []predicates.PredicateFailureReason, error) {
-	return true, nil, nil
-}
-
 func PriorityOne(pod *v1.Pod, meta interface{}, nodeInfo *schedulernodeinfo.NodeInfo) (framework.NodeScore, error) {
 	return framework.NodeScore{}, nil
 }
@@ -186,7 +182,6 @@ func TestSchedulerCreation(t *testing.T) {
 	testSource := "testProvider"
 	eventBroadcaster := events.NewBroadcaster(&events.EventSinkImpl{Interface: client.EventsV1beta1().Events("")})
 
-	RegisterFitPredicate("PredicateOne", PredicateOne)
 	RegisterPriorityMapReduceFunction("PriorityOne", PriorityOne, nil, 1)
 	RegisterAlgorithmProvider(testSource, sets.NewString("PredicateOne"), sets.NewString("PriorityOne"))
 
@@ -449,7 +444,6 @@ func TestSchedulerNoPhantomPodAfterDelete(t *testing.T) {
 		expectErr := &core.FitError{
 			Pod:         secondPod,
 			NumAllNodes: 1,
-			FailedPredicates: core.FailedPredicateMap{},
 			FilteredNodesStatuses: framework.NodeToStatusMap{
 				node.Name: framework.NewStatus(
 					framework.Unschedulable,
@@ -659,7 +653,6 @@ func TestSchedulerFailedSchedulingReasons(t *testing.T) {
 		expectErr := &core.FitError{
 			Pod:                   podWithTooBigResourceRequests,
 			NumAllNodes:           len(nodes),
-			FailedPredicates:      core.FailedPredicateMap{},
 			FilteredNodesStatuses: failedNodeStatues,
 		}
 		if len(fmt.Sprint(expectErr)) > 150 {