implementing predicates ordering

plugin/pkg/scheduler/algorithm/predicates/predicates.go

@@ -51,7 +51,23 @@ import (
 const (
 	MatchInterPodAffinity               = "MatchInterPodAffinity"
 	CheckVolumeBinding                  = "CheckVolumeBinding"
-
+	CheckNodeConditionPred              = "CheckNodeCondition"
+	GeneralPred                         = "GeneralPredicates"
+	HostNamePred                        = "HostName"
+	PodFitsHostPortsPred                = "PodFitsHostPorts"
+	MatchNodeSelectorPred               = "MatchNodeSelector"
+	PodFitsResourcesPred                = "PodFitsResources"
+	NoDiskConflictPred                  = "NoDiskConflict"
+	PodToleratesNodeTaintsPred          = "PodToleratesNodeTaints"
+	PodToleratesNodeNoExecuteTaintsPred = "PodToleratesNodeNoExecuteTaints"
+	CheckNodeLabelPresencePred          = "CheckNodeLabelPresence"
+	checkServiceAffinityPred            = "checkServiceAffinity"
+	MaxEBSVolumeCountPred               = "MaxEBSVolumeCount"
+	MaxGCEPDVolumeCountPred             = "MaxGCEPDVolumeCount"
+	MaxAzureDiskVolumeCountPred         = "MaxAzureDiskVolumeCount"
+	NoVolumeZoneConflictPred            = "NoVolumeZoneConflict"
+	CheckNodeMemoryPressurePred         = "CheckNodeMemoryPressure"
+	CheckNodeDiskPressure               = "CheckNodeDiskPressure"
 	// DefaultMaxGCEPDVolumes defines the maximum number of PD Volumes for GCE
 	// GCE instances can have up to 16 PD volumes attached.
 	DefaultMaxGCEPDVolumes = 16
@@ -79,6 +95,21 @@ const (
 // For example:
 // https://github.com/kubernetes/kubernetes/blob/36a218e/plugin/pkg/scheduler/factory/factory.go#L422
 
+// IMPORTANT: this list contains the ordering of the predicates, if you develop a new predicates
+// it is mandatory to add its name on this list.
+// otherwise it won't be processed, see generic_scheduler#podFitsOnNode()
+// the order is based on the restrictiveness & complexity of predicates
+// design doc: https://github.com/kubernetes/community/blob/master/contributors/design-proposals/scheduling/predicates-ordering.md
+var (
+	predicatesOrdering = []string{CheckNodeConditionPred,
+		GeneralPred, HostNamePred, PodFitsHostPortsPred,
+		MatchNodeSelectorPred, PodFitsResourcesPred, NoDiskConflictPred,
+		PodToleratesNodeTaintsPred, PodToleratesNodeNoExecuteTaintsPred, CheckNodeLabelPresencePred,
+		checkServiceAffinityPred, MaxEBSVolumeCountPred, MaxGCEPDVolumeCountPred,
+		MaxAzureDiskVolumeCountPred, CheckVolumeBinding, NoVolumeZoneConflictPred,
+		CheckNodeMemoryPressurePred, CheckNodeDiskPressure, MatchInterPodAffinity}
+)
+
 // NodeInfo: Other types for predicate functions...
 type NodeInfo interface {
 	GetNodeInfo(nodeID string) (*v1.Node, error)
@@ -93,6 +124,14 @@ type CachedPersistentVolumeInfo struct {
 	corelisters.PersistentVolumeLister
 }
 
+func GetPredicatesOrdering() []string {
+	return predicatesOrdering
+}
+
+func SetPredicatesOrdering(names []string) {
+	predicatesOrdering = names
+}
+
 func (c *CachedPersistentVolumeInfo) GetPersistentVolumeInfo(pvID string) (*v1.PersistentVolume, error) {
 	return c.Get(pvID)
 }

plugin/pkg/scheduler/core/generic_scheduler.go

@@ -444,7 +444,9 @@ func podFitsOnNode(
 		// TODO(bsalamat): consider using eCache and adding proper eCache invalidations
 		// when pods are nominated or their nominations change.
 		eCacheAvailable = eCacheAvailable && !podsAdded
-		for predicateKey, predicate := range predicateFuncs {
+		for _, predicateKey := range predicates.GetPredicatesOrdering() {
+			//TODO (yastij) : compute average predicate restrictiveness to export it as promethus metric
+			if predicate, exist := predicateFuncs[predicateKey]; exist {
 				if eCacheAvailable {
 					// PredicateWithECache will return its cached predicate results.
 					fit, reasons, invalid = ecache.PredicateWithECache(pod.GetName(), info.Node().GetName(), predicateKey, equivalenceHash)
@@ -475,6 +477,7 @@ func podFitsOnNode(
 				}
 			}
 		}
+	}
 
 	// TODO(bsalamat): This way of updating equiv. cache has a race condition against
 	// cache invalidations invoked in event handlers. This race has existed despite locks

plugin/pkg/scheduler/core/generic_scheduler_test.go

@@ -42,6 +42,10 @@ import (
 	schedulertesting "k8s.io/kubernetes/plugin/pkg/scheduler/testing"
 )
 
+var (
+	order = []string{"false", "true", "matches", "nopods", predicates.MatchInterPodAffinity}
+)
+
 func falsePredicate(pod *v1.Pod, meta algorithm.PredicateMetadata, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
 	return false, []algorithm.PredicateFailureReason{algorithmpredicates.ErrFakePredicate}, nil
 }
@@ -181,6 +185,7 @@ func TestSelectHost(t *testing.T) {
 }
 
 func TestGenericScheduler(t *testing.T) {
+	predicates.SetPredicatesOrdering(order)
 	tests := []struct {
 		name          string
 		predicates    map[string]algorithm.FitPredicate
@@ -401,6 +406,7 @@ func TestGenericScheduler(t *testing.T) {
 }
 
 func TestFindFitAllError(t *testing.T) {
+	predicates.SetPredicatesOrdering(order)
 	nodes := []string{"3", "2", "1"}
 	predicates := map[string]algorithm.FitPredicate{"true": truePredicate, "false": falsePredicate}
 	nodeNameToInfo := map[string]*schedulercache.NodeInfo{
@@ -430,8 +436,9 @@ func TestFindFitAllError(t *testing.T) {
 }
 
 func TestFindFitSomeError(t *testing.T) {
+	predicates.SetPredicatesOrdering(order)
 	nodes := []string{"3", "2", "1"}
-	predicates := map[string]algorithm.FitPredicate{"true": truePredicate, "match": matchesPredicate}
+	predicates := map[string]algorithm.FitPredicate{"true": truePredicate, "matches": matchesPredicate}
 	pod := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "1"}}
 	nodeNameToInfo := map[string]*schedulercache.NodeInfo{
 		"3": schedulercache.NewNodeInfo(),
@@ -741,6 +748,7 @@ var negPriority, lowPriority, midPriority, highPriority, veryHighPriority = int3
 // TestSelectNodesForPreemption tests selectNodesForPreemption. This test assumes
 // that podsFitsOnNode works correctly and is tested separately.
 func TestSelectNodesForPreemption(t *testing.T) {
+	predicates.SetPredicatesOrdering(order)
 	tests := []struct {
 		name                 string
 		predicates           map[string]algorithm.FitPredicate
@@ -879,6 +887,7 @@ func TestSelectNodesForPreemption(t *testing.T) {
 
 // TestPickOneNodeForPreemption tests pickOneNodeForPreemption.
 func TestPickOneNodeForPreemption(t *testing.T) {
+	predicates.SetPredicatesOrdering(order)
 	tests := []struct {
 		name       string
 		predicates map[string]algorithm.FitPredicate

plugin/pkg/scheduler/scheduler_test.go

@@ -43,6 +43,8 @@ import (
 	"k8s.io/kubernetes/plugin/pkg/scheduler/volumebinder"
 )
 
+var order = []string{"VolumeBindingChecker"}
+
 type fakeBinder struct {
 	b func(binding *v1.Binding) error
 }
@@ -637,6 +639,7 @@ func makePredicateError(failReason string) error {
 }
 
 func TestSchedulerWithVolumeBinding(t *testing.T) {
+	predicates.SetPredicatesOrdering(order)
 	findErr := fmt.Errorf("find err")
 	assumeErr := fmt.Errorf("assume err")
 	bindErr := fmt.Errorf("bind err")