Move scheduler code out of plugin directory.

This moves plugin/pkg/scheduler to pkg/scheduler and
plugin/cmd/kube-scheduler to cmd/kube-scheduler.

Bulk of the work was done with gomvpkg, except for kube-scheduler main
package.

pkg/scheduler/algorithm/scheduler_interface.go

@@ -0,0 +1,61 @@
+/*
+Copyright 2014 The Kubernetes Authors.
+
+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.
+*/
+
+package algorithm
+
+import (
+	"k8s.io/api/core/v1"
+	schedulerapi "k8s.io/kubernetes/pkg/scheduler/api"
+	"k8s.io/kubernetes/pkg/scheduler/schedulercache"
+)
+
+// SchedulerExtender is an interface for external processes to influence scheduling
+// decisions made by Kubernetes. This is typically needed for resources not directly
+// managed by Kubernetes.
+type SchedulerExtender interface {
+	// Filter based on extender-implemented predicate functions. The filtered list is
+	// expected to be a subset of the supplied list. failedNodesMap optionally contains
+	// the list of failed nodes and failure reasons.
+	Filter(pod *v1.Pod, nodes []*v1.Node, nodeNameToInfo map[string]*schedulercache.NodeInfo) (filteredNodes []*v1.Node, failedNodesMap schedulerapi.FailedNodesMap, err error)
+
+	// Prioritize based on extender-implemented priority functions. The returned scores & weight
+	// are used to compute the weighted score for an extender. The weighted scores are added to
+	// the scores computed  by Kubernetes scheduler. The total scores are used to do the host selection.
+	Prioritize(pod *v1.Pod, nodes []*v1.Node) (hostPriorities *schedulerapi.HostPriorityList, weight int, err error)
+
+	// Bind delegates the action of binding a pod to a node to the extender.
+	Bind(binding *v1.Binding) error
+
+	// IsBinder returns whether this extender is configured for the Bind method.
+	IsBinder() bool
+}
+
+// ScheduleAlgorithm is an interface implemented by things that know how to schedule pods
+// onto machines.
+type ScheduleAlgorithm interface {
+	Schedule(*v1.Pod, NodeLister) (selectedMachine string, 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
+	// list of pods whose nominated node name should be removed, and error if any.
+	Preempt(*v1.Pod, NodeLister, error) (selectedNode *v1.Node, preemptedPods []*v1.Pod, cleanupNominatedPods []*v1.Pod, err error)
+	// Predicates() returns a pointer to a map of predicate functions. This is
+	// exposed for testing.
+	Predicates() map[string]FitPredicate
+	// Prioritizers returns a slice of priority config. This is exposed for
+	// testing.
+	Prioritizers() []PriorityConfig
+}