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/predicates/error.go

@@ -0,0 +1,118 @@
+/*
+Copyright 2016 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 predicates
+
+import (
+	"fmt"
+
+	"k8s.io/api/core/v1"
+)
+
+var (
+	// The predicateName tries to be consistent as the predicate name used in DefaultAlgorithmProvider defined in
+	// defaults.go (which tend to be stable for backward compatibility)
+
+	// NOTE: If you add a new predicate failure error for a predicate that can never
+	// be made to pass by removing pods, or you change an existing predicate so that
+	// it can never be made to pass by removing pods, you need to add the predicate
+	// failure error in nodesWherePreemptionMightHelp() in scheduler/core/generic_scheduler.go
+	ErrDiskConflict                          = newPredicateFailureError("NoDiskConflict")
+	ErrVolumeZoneConflict                    = newPredicateFailureError("NoVolumeZoneConflict")
+	ErrNodeSelectorNotMatch                  = newPredicateFailureError("MatchNodeSelector")
+	ErrPodAffinityNotMatch                   = newPredicateFailureError("MatchInterPodAffinity")
+	ErrPodAffinityRulesNotMatch              = newPredicateFailureError("PodAffinityRulesNotMatch")
+	ErrPodAntiAffinityRulesNotMatch          = newPredicateFailureError("PodAntiAffinityRulesNotMatch")
+	ErrExistingPodsAntiAffinityRulesNotMatch = newPredicateFailureError("ExistingPodsAntiAffinityRulesNotMatch")
+	ErrTaintsTolerationsNotMatch             = newPredicateFailureError("PodToleratesNodeTaints")
+	ErrPodNotMatchHostName                   = newPredicateFailureError("HostName")
+	ErrPodNotFitsHostPorts                   = newPredicateFailureError("PodFitsHostPorts")
+	ErrNodeLabelPresenceViolated             = newPredicateFailureError("CheckNodeLabelPresence")
+	ErrServiceAffinityViolated               = newPredicateFailureError("CheckServiceAffinity")
+	ErrMaxVolumeCountExceeded                = newPredicateFailureError("MaxVolumeCount")
+	ErrNodeUnderMemoryPressure               = newPredicateFailureError("NodeUnderMemoryPressure")
+	ErrNodeUnderDiskPressure                 = newPredicateFailureError("NodeUnderDiskPressure")
+	ErrNodeOutOfDisk                         = newPredicateFailureError("NodeOutOfDisk")
+	ErrNodeNotReady                          = newPredicateFailureError("NodeNotReady")
+	ErrNodeNetworkUnavailable                = newPredicateFailureError("NodeNetworkUnavailable")
+	ErrNodeUnschedulable                     = newPredicateFailureError("NodeUnschedulable")
+	ErrNodeUnknownCondition                  = newPredicateFailureError("NodeUnknownCondition")
+	ErrVolumeNodeConflict                    = newPredicateFailureError("VolumeNodeAffinityConflict")
+	ErrVolumeBindConflict                    = newPredicateFailureError("VolumeBindingNoMatch")
+	// ErrFakePredicate is used for test only. The fake predicates returning false also returns error
+	// as ErrFakePredicate.
+	ErrFakePredicate = newPredicateFailureError("FakePredicateError")
+)
+
+// InsufficientResourceError is an error type that indicates what kind of resource limit is
+// hit and caused the unfitting failure.
+type InsufficientResourceError struct {
+	// resourceName is the name of the resource that is insufficient
+	ResourceName v1.ResourceName
+	requested    int64
+	used         int64
+	capacity     int64
+}
+
+func NewInsufficientResourceError(resourceName v1.ResourceName, requested, used, capacity int64) *InsufficientResourceError {
+	return &InsufficientResourceError{
+		ResourceName: resourceName,
+		requested:    requested,
+		used:         used,
+		capacity:     capacity,
+	}
+}
+
+func (e *InsufficientResourceError) Error() string {
+	return fmt.Sprintf("Node didn't have enough resource: %s, requested: %d, used: %d, capacity: %d",
+		e.ResourceName, e.requested, e.used, e.capacity)
+}
+
+func (e *InsufficientResourceError) GetReason() string {
+	return fmt.Sprintf("Insufficient %v", e.ResourceName)
+}
+
+func (e *InsufficientResourceError) GetInsufficientAmount() int64 {
+	return e.requested - (e.capacity - e.used)
+}
+
+type PredicateFailureError struct {
+	PredicateName string
+}
+
+func newPredicateFailureError(predicateName string) *PredicateFailureError {
+	return &PredicateFailureError{PredicateName: predicateName}
+}
+
+func (e *PredicateFailureError) Error() string {
+	return fmt.Sprintf("Predicate %s failed", e.PredicateName)
+}
+
+func (e *PredicateFailureError) GetReason() string {
+	return e.PredicateName
+}
+
+type FailureReason struct {
+	reason string
+}
+
+func NewFailureReason(msg string) *FailureReason {
+	return &FailureReason{reason: msg}
+}
+
+func (e *FailureReason) GetReason() string {
+	return e.reason
+}