Small cleanup of scheduler default algorithm provider

plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go

@@ -40,62 +40,30 @@ const (
 	PetSetKind                = "PetSet"
 )
 
-// getMaxVols checks the max PD volumes environment variable, otherwise returning a default value
-func getMaxVols(defaultVal int) int {
-	if rawMaxVols := os.Getenv("KUBE_MAX_PD_VOLS"); rawMaxVols != "" {
-		if parsedMaxVols, err := strconv.Atoi(rawMaxVols); err != nil {
-			glog.Errorf("Unable to parse maxiumum PD volumes value, using default of %v: %v", defaultVal, err)
-		} else if parsedMaxVols <= 0 {
-			glog.Errorf("Maximum PD volumes must be a positive value, using default of %v", defaultVal)
-		} else {
-			return parsedMaxVols
-		}
-	}
-
-	return defaultVal
-}
-
 func init() {
-	factory.RegisterAlgorithmProvider(factory.DefaultProvider, defaultPredicates(), defaultPriorities())
+	// Register functions that extract metadata used by predicates and priorities computations.
-	// Cluster autoscaler friendly scheduling algorithm.
+	factory.RegisterPredicateMetadataProducerFactory(
-	factory.RegisterAlgorithmProvider(ClusterAutoscalerProvider, defaultPredicates(),
+		func(args factory.PluginFactoryArgs) algorithm.MetadataProducer {
-		replace(defaultPriorities(), "LeastRequestedPriority", "MostRequestedPriority"))
+			return predicates.NewPredicateMetadataFactory(args.PodLister)
-
+		})
 	factory.RegisterPriorityMetadataProducerFactory(
 		func(args factory.PluginFactoryArgs) algorithm.MetadataProducer {
 			return priorities.PriorityMetadata
 		})
 
-	factory.RegisterPredicateMetadataProducerFactory(
+	// Retisters algorithm providers. By default we use 'DefaultProvider', but user can specify one to be used
-		func(args factory.PluginFactoryArgs) algorithm.MetadataProducer {
+	// by specifying flag.
-			return predicates.NewPredicateMetadataFactory(args.PodLister)
+	factory.RegisterAlgorithmProvider(factory.DefaultProvider, defaultPredicates(), defaultPriorities())
-		})
+	// Cluster autoscaler friendly scheduling algorithm.
+	factory.RegisterAlgorithmProvider(ClusterAutoscalerProvider, defaultPredicates(),
+		copyAndReplace(defaultPriorities(), "LeastRequestedPriority", "MostRequestedPriority"))
 
-	// EqualPriority is a prioritizer function that gives an equal weight of one to all nodes
+	// Registers predicates and priorities that are not enabled by default, but user can pick when creating his
-	// Register the priority function so that its available
+	// own set of priorities/predicates.
-	// but do not include it as part of the default priorities
-	factory.RegisterPriorityFunction2("EqualPriority", scheduler.EqualPriorityMap, nil, 1)
 
-	// ServiceSpreadingPriority is a priority config factory that spreads pods by minimizing
-	// the number of pods (belonging to the same service) on the same node.
-	// Register the factory so that it's available, but do not include it as part of the default priorities
-	// Largely replaced by "SelectorSpreadPriority", but registered for backward compatibility with 1.0
-	factory.RegisterPriorityConfigFactory(
-		"ServiceSpreadingPriority",
-		factory.PriorityConfigFactory{
-			Function: func(args factory.PluginFactoryArgs) algorithm.PriorityFunction {
-				return priorities.NewSelectorSpreadPriority(args.ServiceLister, algorithm.EmptyControllerLister{}, algorithm.EmptyReplicaSetLister{})
-			},
-			Weight: 1,
-		},
-	)
 	// PodFitsPorts has been replaced by PodFitsHostPorts for better user understanding.
 	// For backwards compatibility with 1.0, PodFitsPorts is registered as well.
 	factory.RegisterFitPredicate("PodFitsPorts", predicates.PodFitsHostPorts)
-	// ImageLocalityPriority prioritizes nodes based on locality of images requested by a pod. Nodes with larger size
-	// of already-installed packages required by the pod will be preferred over nodes with no already-installed
-	// packages required by the pod or a small total size of already-installed packages required by the pod.
-	factory.RegisterPriorityFunction2("ImageLocalityPriority", priorities.ImageLocalityPriorityMap, nil, 1)
 	// Fit is defined based on the absence of port conflicts.
 	// This predicate is actually a default predicate, because it is invoked from
 	// predicates.GeneralPredicates()
@@ -110,25 +78,38 @@ func init() {
 	factory.RegisterFitPredicate("HostName", predicates.PodFitsHost)
 	// Fit is determined by node selector query.
 	factory.RegisterFitPredicate("MatchNodeSelector", predicates.PodSelectorMatches)
-	// Optional, cluster-autoscaler friendly priority function - give used nodes higher priority.
+
-	factory.RegisterPriorityFunction2("MostRequestedPriority", priorities.MostRequestedPriorityMap, nil, 1)
 	// Use equivalence class to speed up predicates & priorities
 	factory.RegisterGetEquivalencePodFunction(GetEquivalencePod)
-}
 
-func replace(set sets.String, replaceWhat, replaceWith string) sets.String {
+	// ServiceSpreadingPriority is a priority config factory that spreads pods by minimizing
-	result := sets.NewString(set.List()...)
+	// the number of pods (belonging to the same service) on the same node.
-	if result.Has(replaceWhat) {
+	// Register the factory so that it's available, but do not include it as part of the default priorities
-		result.Delete(replaceWhat)
+	// Largely replaced by "SelectorSpreadPriority", but registered for backward compatibility with 1.0
-		result.Insert(replaceWith)
+	factory.RegisterPriorityConfigFactory(
-	}
+		"ServiceSpreadingPriority",
-	return result
+		factory.PriorityConfigFactory{
+			Function: func(args factory.PluginFactoryArgs) algorithm.PriorityFunction {
+				return priorities.NewSelectorSpreadPriority(args.ServiceLister, algorithm.EmptyControllerLister{}, algorithm.EmptyReplicaSetLister{})
+			},
+			Weight: 1,
+		},
+	)
+
+	// EqualPriority is a prioritizer function that gives an equal weight of one to all nodes
+	// Register the priority function so that its available
+	// but do not include it as part of the default priorities
+	factory.RegisterPriorityFunction2("EqualPriority", scheduler.EqualPriorityMap, nil, 1)
+	// ImageLocalityPriority prioritizes nodes based on locality of images requested by a pod. Nodes with larger size
+	// of already-installed packages required by the pod will be preferred over nodes with no already-installed
+	// packages required by the pod or a small total size of already-installed packages required by the pod.
+	factory.RegisterPriorityFunction2("ImageLocalityPriority", priorities.ImageLocalityPriorityMap, nil, 1)
+	// Optional, cluster-autoscaler friendly priority function - give used nodes higher priority.
+	factory.RegisterPriorityFunction2("MostRequestedPriority", priorities.MostRequestedPriorityMap, nil, 1)
 }
 
 func defaultPredicates() sets.String {
 	return sets.NewString(
-		// Fit is determined by non-conflicting disk volumes.
-		factory.RegisterFitPredicate("NoDiskConflict", predicates.NoDiskConflict),
 		// Fit is determined by volume zone requirements.
 		factory.RegisterFitPredicateFactory(
 			"NoVolumeZoneConflict",
@@ -154,6 +135,17 @@ func defaultPredicates() sets.String {
 				return predicates.NewMaxPDVolumeCountPredicate(predicates.GCEPDVolumeFilter, maxVols, args.PVInfo, args.PVCInfo)
 			},
 		),
+		// Fit is determined by inter-pod affinity.
+		factory.RegisterFitPredicateFactory(
+			"MatchInterPodAffinity",
+			func(args factory.PluginFactoryArgs) algorithm.FitPredicate {
+				return predicates.NewPodAffinityPredicate(args.NodeInfo, args.PodLister, args.FailureDomains)
+			},
+		),
+
+		// Fit is determined by non-conflicting disk volumes.
+		factory.RegisterFitPredicate("NoDiskConflict", predicates.NoDiskConflict),
+
 		// GeneralPredicates are the predicates that are enforced by all Kubernetes components
 		// (e.g. kubelet and all schedulers)
 		factory.RegisterFitPredicate("GeneralPredicates", predicates.GeneralPredicates),
@@ -169,23 +161,11 @@ func defaultPredicates() sets.String {
 
 		// Fit is determined by node inode pressure condition.
 		factory.RegisterFitPredicate("CheckNodeInodePressure", predicates.CheckNodeInodePressurePredicate),
-
-		// Fit is determined by inter-pod affinity.
-		factory.RegisterFitPredicateFactory(
-			"MatchInterPodAffinity",
-			func(args factory.PluginFactoryArgs) algorithm.FitPredicate {
-				return predicates.NewPodAffinityPredicate(args.NodeInfo, args.PodLister, args.FailureDomains)
-			},
-		),
 	)
 }
 
 func defaultPriorities() sets.String {
 	return sets.NewString(
-		// Prioritize nodes by least requested utilization.
-		factory.RegisterPriorityFunction2("LeastRequestedPriority", priorities.LeastRequestedPriorityMap, nil, 1),
-		// Prioritizes nodes to help achieve balanced resource usage
-		factory.RegisterPriorityFunction2("BalancedResourceAllocation", priorities.BalancedResourceAllocationMap, nil, 1),
 		// spreads pods by minimizing the number of pods (belonging to the same service or replication controller) on the same node.
 		factory.RegisterPriorityConfigFactory(
 			"SelectorSpreadPriority",
@@ -196,11 +176,6 @@ func defaultPriorities() sets.String {
 				Weight: 1,
 			},
 		),
-		// Set this weight large enough to override all other priority functions.
-		// TODO: Figure out a better way to do this, maybe at same time as fixing #24720.
-		factory.RegisterPriorityFunction2("NodePreferAvoidPodsPriority", priorities.CalculateNodePreferAvoidPodsPriorityMap, nil, 10000),
-		factory.RegisterPriorityFunction2("NodeAffinityPriority", priorities.CalculateNodeAffinityPriorityMap, priorities.CalculateNodeAffinityPriorityReduce, 1),
-		factory.RegisterPriorityFunction2("TaintTolerationPriority", priorities.ComputeTaintTolerationPriorityMap, priorities.ComputeTaintTolerationPriorityReduce, 1),
 		// pods should be placed in the same topological domain (e.g. same node, same rack, same zone, same power domain, etc.)
 		// as some other pods, or, conversely, should not be placed in the same topological domain as some other pods.
 		factory.RegisterPriorityConfigFactory(
@@ -212,9 +187,49 @@ func defaultPriorities() sets.String {
 				Weight: 1,
 			},
 		),
+
+		// Prioritize nodes by least requested utilization.
+		factory.RegisterPriorityFunction2("LeastRequestedPriority", priorities.LeastRequestedPriorityMap, nil, 1),
+
+		// Prioritizes nodes to help achieve balanced resource usage
+		factory.RegisterPriorityFunction2("BalancedResourceAllocation", priorities.BalancedResourceAllocationMap, nil, 1),
+
+		// Set this weight large enough to override all other priority functions.
+		// TODO: Figure out a better way to do this, maybe at same time as fixing #24720.
+		factory.RegisterPriorityFunction2("NodePreferAvoidPodsPriority", priorities.CalculateNodePreferAvoidPodsPriorityMap, nil, 10000),
+
+		// Prioritizes nodes that have labels matching NodeAffinity
+		factory.RegisterPriorityFunction2("NodeAffinityPriority", priorities.CalculateNodeAffinityPriorityMap, priorities.CalculateNodeAffinityPriorityReduce, 1),
+
+		// TODO: explain what it does.
+		factory.RegisterPriorityFunction2("TaintTolerationPriority", priorities.ComputeTaintTolerationPriorityMap, priorities.ComputeTaintTolerationPriorityReduce, 1),
 	)
 }
 
+// getMaxVols checks the max PD volumes environment variable, otherwise returning a default value
+func getMaxVols(defaultVal int) int {
+	if rawMaxVols := os.Getenv("KUBE_MAX_PD_VOLS"); rawMaxVols != "" {
+		if parsedMaxVols, err := strconv.Atoi(rawMaxVols); err != nil {
+			glog.Errorf("Unable to parse maxiumum PD volumes value, using default of %v: %v", defaultVal, err)
+		} else if parsedMaxVols <= 0 {
+			glog.Errorf("Maximum PD volumes must be a positive value, using default of %v", defaultVal)
+		} else {
+			return parsedMaxVols
+		}
+	}
+
+	return defaultVal
+}
+
+func copyAndReplace(set sets.String, replaceWhat, replaceWith string) sets.String {
+	result := sets.NewString(set.List()...)
+	if result.Has(replaceWhat) {
+		result.Delete(replaceWhat)
+		result.Insert(replaceWith)
+	}
+	return result
+}
+
 // GetEquivalencePod returns a EquivalencePod which contains a group of pod attributes which can be reused.
 func GetEquivalencePod(pod *api.Pod) interface{} {
 	equivalencePod := EquivalencePod{}