refactor scheduler factory to use plugin architecture style like credentialprovider and cloudprovider for configuring priority functions and fit predicates

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

@@ -0,0 +1,52 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// This is the default algorithm provider for the scheduler.
+package defaults
+
+import (
+	algorithm "github.com/GoogleCloudPlatform/kubernetes/pkg/scheduler"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/scheduler/factory"
+)
+
+func init() {
+	factory.RegisterAlgorithmProvider(factory.DefaultProvider, defaultPredicates(), defaultPriorities())
+}
+
+func defaultPredicates() util.StringSet {
+	return util.NewStringSet(
+		// Fit is defined based on the absence of port conflicts.
+		factory.RegisterFitPredicate("PodFitsPorts", algorithm.PodFitsPorts),
+		// Fit is determined by resource availability
+		factory.RegisterFitPredicate("PodFitsResources", algorithm.NewResourceFitPredicate(factory.MinionLister)),
+		// Fit is determined by non-conflicting disk volumes
+		factory.RegisterFitPredicate("NoDiskConflict", algorithm.NoDiskConflict),
+		// Fit is determined by node selector query
+		factory.RegisterFitPredicate("MatchNodeSelector", algorithm.NewSelectorMatchPredicate(factory.MinionLister)),
+	)
+}
+
+func defaultPriorities() util.StringSet {
+	return util.NewStringSet(
+		// Prioritize nodes by least requested utilization.
+		factory.RegisterPriorityFunction("LeastRequestedPriority", algorithm.LeastRequestedPriority, 1),
+		// spreads pods by minimizing the number of pods on the same minion with the same labels.
+		factory.RegisterPriorityFunction("SpreadingPriority", algorithm.CalculateSpreadPriority, 1),
+		// EqualPriority is a prioritizer function that gives an equal weight of one to all minions
+		factory.RegisterPriorityFunction("EqualPriority", algorithm.EqualPriority, 0),
+	)
+}