[scheduler] Modify the scheduling result struct and improve logging for successful binding

pkg/scheduler/core/extender_test.go

@@ -18,6 +18,7 @@ package core
 
 import (
 	"fmt"
+	"reflect"
 	"testing"
 	"time"
 
@@ -337,13 +338,13 @@ var _ algorithm.SchedulerExtender = &FakeExtender{}
 
 func TestGenericSchedulerWithExtenders(t *testing.T) {
 	tests := []struct {
-		name         string
-		predicates   map[string]predicates.FitPredicate
-		prioritizers []algorithm.PriorityConfig
-		extenders    []FakeExtender
-		nodes        []string
-		expectedHost string
-		expectsErr   bool
+		name           string
+		predicates     map[string]predicates.FitPredicate
+		prioritizers   []algorithm.PriorityConfig
+		extenders      []FakeExtender
+		nodes          []string
+		expectedResult ScheduleResult
+		expectsErr     bool
 	}{
 		{
 			predicates:   map[string]predicates.FitPredicate{"true": truePredicate},
@@ -386,9 +387,13 @@ func TestGenericSchedulerWithExtenders(t *testing.T) {
 					predicates: []fitPredicate{machine1PredicateExtender},
 				},
 			},
-			nodes:        []string{"machine1", "machine2"},
-			expectedHost: "machine1",
-			name:         "test 3",
+			nodes: []string{"machine1", "machine2"},
+			expectedResult: ScheduleResult{
+				SuggestedHost:  "machine1",
+				EvaluatedNodes: 2,
+				FeasibleNodes:  1,
+			},
+			name: "test 3",
 		},
 		{
 			predicates:   map[string]predicates.FitPredicate{"true": truePredicate},
@@ -415,9 +420,13 @@ func TestGenericSchedulerWithExtenders(t *testing.T) {
 					weight:       1,
 				},
 			},
-			nodes:        []string{"machine1"},
-			expectedHost: "machine1",
-			name:         "test 5",
+			nodes: []string{"machine1"},
+			expectedResult: ScheduleResult{
+				SuggestedHost:  "machine1",
+				EvaluatedNodes: 1,
+				FeasibleNodes:  1,
+			},
+			name: "test 5",
 		},
 		{
 			predicates:   map[string]predicates.FitPredicate{"true": truePredicate},
@@ -434,9 +443,13 @@ func TestGenericSchedulerWithExtenders(t *testing.T) {
 					weight:       5,
 				},
 			},
-			nodes:        []string{"machine1", "machine2"},
-			expectedHost: "machine2",
-			name:         "test 6",
+			nodes: []string{"machine1", "machine2"},
+			expectedResult: ScheduleResult{
+				SuggestedHost:  "machine2",
+				EvaluatedNodes: 2,
+				FeasibleNodes:  2,
+			},
+			name: "test 6",
 		},
 		{
 			predicates:   map[string]predicates.FitPredicate{"true": truePredicate},
@@ -448,9 +461,13 @@ func TestGenericSchedulerWithExtenders(t *testing.T) {
 					weight:       1,
 				},
 			},
-			nodes:        []string{"machine1", "machine2"},
-			expectedHost: "machine2", // machine2 has higher score
-			name:         "test 7",
+			nodes: []string{"machine1", "machine2"},
+			expectedResult: ScheduleResult{
+				SuggestedHost:  "machine2",
+				EvaluatedNodes: 2,
+				FeasibleNodes:  2,
+			}, // machine2 has higher score
+			name: "test 7",
 		},
 		{
 			// Scheduler is expected to not send pod to extender in
@@ -469,10 +486,14 @@ func TestGenericSchedulerWithExtenders(t *testing.T) {
 					unInterested: true,
 				},
 			},
-			nodes:        []string{"machine1", "machine2"},
-			expectsErr:   false,
-			expectedHost: "machine2", // machine2 has higher score
-			name:         "test 8",
+			nodes:      []string{"machine1", "machine2"},
+			expectsErr: false,
+			expectedResult: ScheduleResult{
+				SuggestedHost:  "machine2",
+				EvaluatedNodes: 2,
+				FeasibleNodes:  2,
+			}, // machine2 has higher score
+			name: "test 8",
 		},
 		{
 			// Scheduling is expected to not fail in
@@ -491,10 +512,14 @@ func TestGenericSchedulerWithExtenders(t *testing.T) {
 					predicates: []fitPredicate{machine1PredicateExtender},
 				},
 			},
-			nodes:        []string{"machine1", "machine2"},
-			expectsErr:   false,
-			expectedHost: "machine1",
-			name:         "test 9",
+			nodes:      []string{"machine1", "machine2"},
+			expectsErr: false,
+			expectedResult: ScheduleResult{
+				SuggestedHost:  "machine1",
+				EvaluatedNodes: 2,
+				FeasibleNodes:  1,
+			},
+			name: "test 9",
 		},
 	}
 
@@ -525,18 +550,19 @@ func TestGenericSchedulerWithExtenders(t *testing.T) {
 				false,
 				schedulerapi.DefaultPercentageOfNodesToScore)
 			podIgnored := &v1.Pod{}
-			machine, err := scheduler.Schedule(podIgnored, schedulertesting.FakeNodeLister(makeNodeList(test.nodes)))
+			result, err := scheduler.Schedule(podIgnored, schedulertesting.FakeNodeLister(makeNodeList(test.nodes)))
 			if test.expectsErr {
 				if err == nil {
-					t.Errorf("Unexpected non-error, machine %s", machine)
+					t.Errorf("Unexpected non-error, result %+v", result)
 				}
 			} else {
 				if err != nil {
 					t.Errorf("Unexpected error: %v", err)
 					return
 				}
-				if test.expectedHost != machine {
-					t.Errorf("Expected: %s, Saw: %s", test.expectedHost, machine)
+
+				if !reflect.DeepEqual(result, test.expectedResult) {
+					t.Errorf("Expected: %+v, Saw: %+v", test.expectedResult, result)
 				}
 			}
 		})

pkg/scheduler/core/generic_scheduler.go

@@ -104,7 +104,7 @@ func (f *FitError) Error() string {
 // onto machines.
 // TODO: Rename this type.
 type ScheduleAlgorithm interface {
-	Schedule(*v1.Pod, algorithm.NodeLister) (selectedMachine string, err error)
+	Schedule(*v1.Pod, algorithm.NodeLister) (scheduleResult ScheduleResult, err error)
 	// Preempt receives scheduling errors for a pod and tries to create room for
 	// the pod by preempting lower priority pods if possible.
 	// It returns the node where preemption happened, a list of preempted pods, a
@@ -118,6 +118,17 @@ type ScheduleAlgorithm interface {
 	Prioritizers() []algorithm.PriorityConfig
 }
 
+// ScheduleResult represents the result of one pod scheduled. It will contain
+// the final selected Node, along with the selected intermediate information.
+type ScheduleResult struct {
+	// Name of the scheduler suggest host
+	SuggestedHost string
+	// Number of nodes scheduler evaluated on one pod scheduled
+	EvaluatedNodes int
+	// Number of feasible nodes on one pod scheduled
+	FeasibleNodes int
+}
+
 type genericScheduler struct {
 	cache                    schedulerinternalcache.Cache
 	schedulingQueue          internalqueue.SchedulingQueue
@@ -147,36 +158,35 @@ func (g *genericScheduler) snapshot() error {
 // Schedule tries to schedule the given pod to one of the nodes in the node list.
 // If it succeeds, it will return the name of the node.
 // If it fails, it will return a FitError error with reasons.
-func (g *genericScheduler) Schedule(pod *v1.Pod, nodeLister algorithm.NodeLister) (string, error) {
+func (g *genericScheduler) Schedule(pod *v1.Pod, nodeLister algorithm.NodeLister) (result ScheduleResult, err error) {
 	trace := utiltrace.New(fmt.Sprintf("Scheduling %s/%s", pod.Namespace, pod.Name))
 	defer trace.LogIfLong(100 * time.Millisecond)
 
 	if err := podPassesBasicChecks(pod, g.pvcLister); err != nil {
-		return "", err
+		return result, err
 	}
 
 	nodes, err := nodeLister.List()
 	if err != nil {
-		return "", err
+		return result, err
 	}
 	if len(nodes) == 0 {
-		return "", ErrNoNodesAvailable
+		return result, ErrNoNodesAvailable
 	}
 
-	err = g.snapshot()
-	if err != nil {
-		return "", err
+	if err := g.snapshot(); err != nil {
+		return result, err
 	}
 
 	trace.Step("Computing predicates")
 	startPredicateEvalTime := time.Now()
 	filteredNodes, failedPredicateMap, err := g.findNodesThatFit(pod, nodes)
 	if err != nil {
-		return "", err
+		return result, err
 	}
 
 	if len(filteredNodes) == 0 {
-		return "", &FitError{
+		return result, &FitError{
 			Pod:              pod,
 			NumAllNodes:      len(nodes),
 			FailedPredicates: failedPredicateMap,
@@ -190,19 +200,29 @@ func (g *genericScheduler) Schedule(pod *v1.Pod, nodeLister algorithm.NodeLister
 	// When only one node after predicate, just use it.
 	if len(filteredNodes) == 1 {
 		metrics.SchedulingAlgorithmPriorityEvaluationDuration.Observe(metrics.SinceInMicroseconds(startPriorityEvalTime))
-		return filteredNodes[0].Name, nil
+		return ScheduleResult{
+			SuggestedHost:  filteredNodes[0].Name,
+			EvaluatedNodes: 1 + len(failedPredicateMap),
+			FeasibleNodes:  1,
+		}, nil
 	}
 
 	metaPrioritiesInterface := g.priorityMetaProducer(pod, g.cachedNodeInfoMap)
 	priorityList, err := PrioritizeNodes(pod, g.cachedNodeInfoMap, metaPrioritiesInterface, g.prioritizers, filteredNodes, g.extenders)
 	if err != nil {
-		return "", err
+		return result, err
 	}
 	metrics.SchedulingAlgorithmPriorityEvaluationDuration.Observe(metrics.SinceInMicroseconds(startPriorityEvalTime))
 	metrics.SchedulingLatency.WithLabelValues(metrics.PriorityEvaluation).Observe(metrics.SinceInSeconds(startPriorityEvalTime))
 
 	trace.Step("Selecting host")
-	return g.selectHost(priorityList)
+
+	host, err := g.selectHost(priorityList)
+	return ScheduleResult{
+		SuggestedHost:  host,
+		EvaluatedNodes: len(filteredNodes) + len(failedPredicateMap),
+		FeasibleNodes:  len(filteredNodes),
+	}, err
 }
 
 // Prioritizers returns a slice containing all the scheduler's priority

pkg/scheduler/core/generic_scheduler_test.go

@@ -482,13 +482,13 @@ func TestGenericScheduler(t *testing.T) {
 				test.alwaysCheckAllPredicates,
 				false,
 				schedulerapi.DefaultPercentageOfNodesToScore)
-			machine, err := scheduler.Schedule(test.pod, schedulertesting.FakeNodeLister(makeNodeList(test.nodes)))
+			result, err := scheduler.Schedule(test.pod, schedulertesting.FakeNodeLister(makeNodeList(test.nodes)))
 
 			if !reflect.DeepEqual(err, test.wErr) {
 				t.Errorf("Unexpected error: %v, expected: %v", err, test.wErr)
 			}
-			if test.expectedHosts != nil && !test.expectedHosts.Has(machine) {
-				t.Errorf("Expected: %s, got: %s", test.expectedHosts, machine)
+			if test.expectedHosts != nil && !test.expectedHosts.Has(result.SuggestedHost) {
+				t.Errorf("Expected: %s, got: %s", test.expectedHosts, result.SuggestedHost)
 			}
 		})
 	}

pkg/scheduler/scheduler.go

@@ -291,15 +291,16 @@ func (sched *Scheduler) recordSchedulingFailure(pod *v1.Pod, err error, reason s
 	})
 }
 
-// schedule implements the scheduling algorithm and returns the suggested host.
-func (sched *Scheduler) schedule(pod *v1.Pod) (string, error) {
-	host, err := sched.config.Algorithm.Schedule(pod, sched.config.NodeLister)
+// schedule implements the scheduling algorithm and returns the suggested result(host,
+// evaluated nodes number,feasible nodes number).
+func (sched *Scheduler) schedule(pod *v1.Pod) (core.ScheduleResult, error) {
+	result, err := sched.config.Algorithm.Schedule(pod, sched.config.NodeLister)
 	if err != nil {
 		pod = pod.DeepCopy()
 		sched.recordSchedulingFailure(pod, err, v1.PodReasonUnschedulable, err.Error())
-		return "", err
+		return core.ScheduleResult{}, err
 	}
-	return host, err
+	return result, err
 }
 
 // preempt tries to create room for a pod that has failed to schedule, by preempting lower priority pods if possible.
@@ -468,7 +469,7 @@ func (sched *Scheduler) scheduleOne() {
 
 	// Synchronously attempt to find a fit for the pod.
 	start := time.Now()
-	suggestedHost, err := sched.schedule(pod)
+	scheduleResult, err := sched.schedule(pod)
 	if err != nil {
 		// schedule() may have failed because the pod would not fit on any host, so we try to
 		// preempt, with the expectation that the next time the pod is tried for scheduling it
@@ -507,7 +508,7 @@ func (sched *Scheduler) scheduleOne() {
 	// Otherwise, binding of volumes is started after the pod is assumed, but before pod binding.
 	//
 	// This function modifies 'assumedPod' if volume binding is required.
-	allBound, err := sched.assumeVolumes(assumedPod, suggestedHost)
+	allBound, err := sched.assumeVolumes(assumedPod, scheduleResult.SuggestedHost)
 	if err != nil {
 		klog.Errorf("error assuming volumes: %v", err)
 		metrics.PodScheduleErrors.Inc()
@@ -516,7 +517,7 @@ func (sched *Scheduler) scheduleOne() {
 
 	// Run "reserve" plugins.
 	for _, pl := range plugins.ReservePlugins() {
-		if err := pl.Reserve(plugins, assumedPod, suggestedHost); err != nil {
+		if err := pl.Reserve(plugins, assumedPod, scheduleResult.SuggestedHost); err != nil {
 			klog.Errorf("error while running %v reserve plugin for pod %v: %v", pl.Name(), assumedPod.Name, err)
 			sched.recordSchedulingFailure(assumedPod, err, SchedulerError,
 				fmt.Sprintf("reserve plugin %v failed", pl.Name()))
@@ -524,8 +525,8 @@ func (sched *Scheduler) scheduleOne() {
 			return
 		}
 	}
-	// assume modifies `assumedPod` by setting NodeName=suggestedHost
-	err = sched.assume(assumedPod, suggestedHost)
+	// assume modifies `assumedPod` by setting NodeName=scheduleResult.SuggestedHost
+	err = sched.assume(assumedPod, scheduleResult.SuggestedHost)
 	if err != nil {
 		klog.Errorf("error assuming pod: %v", err)
 		metrics.PodScheduleErrors.Inc()
@@ -545,7 +546,7 @@ func (sched *Scheduler) scheduleOne() {
 
 		// Run "prebind" plugins.
 		for _, pl := range plugins.PrebindPlugins() {
-			approved, err := pl.Prebind(plugins, assumedPod, suggestedHost)
+			approved, err := pl.Prebind(plugins, assumedPod, scheduleResult.SuggestedHost)
 			if err != nil {
 				approved = false
 				klog.Errorf("error while running %v prebind plugin for pod %v: %v", pl.Name(), assumedPod.Name, err)
@@ -571,7 +572,7 @@ func (sched *Scheduler) scheduleOne() {
 			ObjectMeta: metav1.ObjectMeta{Namespace: assumedPod.Namespace, Name: assumedPod.Name, UID: assumedPod.UID},
 			Target: v1.ObjectReference{
 				Kind: "Node",
-				Name: suggestedHost,
+				Name: scheduleResult.SuggestedHost,
 			},
 		})
 		metrics.E2eSchedulingLatency.Observe(metrics.SinceInMicroseconds(start))
@@ -579,6 +580,7 @@ func (sched *Scheduler) scheduleOne() {
 			klog.Errorf("error binding pod: %v", err)
 			metrics.PodScheduleErrors.Inc()
 		} else {
+			klog.V(2).Infof("pod %v/%v is bound successfully on node %v, %d nodes evaluated, %d nodes were found feasible", assumedPod.Namespace, assumedPod.Name, scheduleResult.SuggestedHost, scheduleResult.EvaluatedNodes, scheduleResult.FeasibleNodes)
 			metrics.PodScheduleSuccesses.Inc()
 		}
 	}()

pkg/scheduler/scheduler_test.go

@@ -145,12 +145,12 @@ func PriorityOne(pod *v1.Pod, nodeNameToInfo map[string]*schedulernodeinfo.NodeI
 }
 
 type mockScheduler struct {
-	machine string
-	err     error
+	result core.ScheduleResult
+	err    error
 }
 
-func (es mockScheduler) Schedule(pod *v1.Pod, ml algorithm.NodeLister) (string, error) {
-	return es.machine, es.err
+func (es mockScheduler) Schedule(pod *v1.Pod, ml algorithm.NodeLister) (core.ScheduleResult, error) {
+	return es.result, es.err
 }
 
 func (es mockScheduler) Predicates() map[string]predicates.FitPredicate {
@@ -222,7 +222,7 @@ func TestScheduler(t *testing.T) {
 		{
 			name:             "bind assumed pod scheduled",
 			sendPod:          podWithID("foo", ""),
-			algo:             mockScheduler{testNode.Name, nil},
+			algo:             mockScheduler{core.ScheduleResult{SuggestedHost: testNode.Name, EvaluatedNodes: 1, FeasibleNodes: 1}, nil},
 			expectBind:       &v1.Binding{ObjectMeta: metav1.ObjectMeta{Name: "foo", UID: types.UID("foo")}, Target: v1.ObjectReference{Kind: "Node", Name: testNode.Name}},
 			expectAssumedPod: podWithID("foo", testNode.Name),
 			eventReason:      "Scheduled",
@@ -230,7 +230,7 @@ func TestScheduler(t *testing.T) {
 		{
 			name:           "error pod failed scheduling",
 			sendPod:        podWithID("foo", ""),
-			algo:           mockScheduler{testNode.Name, errS},
+			algo:           mockScheduler{core.ScheduleResult{SuggestedHost: testNode.Name, EvaluatedNodes: 1, FeasibleNodes: 1}, errS},
 			expectError:    errS,
 			expectErrorPod: podWithID("foo", ""),
 			eventReason:    "FailedScheduling",
@@ -238,7 +238,7 @@ func TestScheduler(t *testing.T) {
 		{
 			name:             "error bind forget pod failed scheduling",
 			sendPod:          podWithID("foo", ""),
-			algo:             mockScheduler{testNode.Name, nil},
+			algo:             mockScheduler{core.ScheduleResult{SuggestedHost: testNode.Name, EvaluatedNodes: 1, FeasibleNodes: 1}, nil},
 			expectBind:       &v1.Binding{ObjectMeta: metav1.ObjectMeta{Name: "foo", UID: types.UID("foo")}, Target: v1.ObjectReference{Kind: "Node", Name: testNode.Name}},
 			expectAssumedPod: podWithID("foo", testNode.Name),
 			injectBindError:  errB,
@@ -248,7 +248,7 @@ func TestScheduler(t *testing.T) {
 			eventReason:      "FailedScheduling",
 		}, {
 			sendPod:     deletingPod("foo"),
-			algo:        mockScheduler{"", nil},
+			algo:        mockScheduler{core.ScheduleResult{}, nil},
 			eventReason: "FailedScheduling",
 		},
 	}