Change equivalence hash function.

This changes the equivalence class hashing function to use as inputs all
the Pod fields which are read by FitPredicates. Before we used a
combination of OwnerReference and PersistentVolumeClaim info, which was
a close approximation. The new method ensures that hashing remains
correct regardless of controller behavior.

The PVCSet field can be removed from equivalencePod because it is
implicitly included in the Volume list.

Tests are now broken.

pkg/scheduler/algorithm/predicates/utils.go

@@ -17,11 +17,8 @@ limitations under the License.
 package predicates
 
 import (
-	"github.com/golang/glog"
 	"k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
-	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/kubernetes/pkg/scheduler/algorithm"
 	schedutil "k8s.io/kubernetes/pkg/scheduler/util"
 )
@@ -83,53 +80,35 @@ func NewEquivalencePodGenerator(pvcInfo PersistentVolumeClaimInfo) algorithm.Get
 	return g.getEquivalencePod
 }
 
-// GetEquivalencePod returns a EquivalencePod which contains a group of pod attributes which can be reused.
+// GetEquivalencePod returns a equivalencePod which contains a group of pod attributes which can be reused.
 func (e *EquivalencePodGenerator) getEquivalencePod(pod *v1.Pod) interface{} {
-	// For now we only consider pods:
-	// 1. OwnerReferences is Controller
-	// 2. with same OwnerReferences
-	// 3. with same PVC claim
-	// to be equivalent
-	for _, ref := range pod.OwnerReferences {
-		if ref.Controller != nil && *ref.Controller {
-			if pvcSet, err := e.getPVCSet(pod); err == nil {
-				// A pod can only belongs to one controller, so let's return.
-				return &EquivalencePod{
-					ControllerRef: ref,
-					PVCSet:        pvcSet,
-				}
-			} else {
-				// If error encountered, log warning and return nil (i.e. no equivalent pod found)
-				glog.Warningf("[EquivalencePodGenerator] for pod: %v failed due to: %v", pod.GetName(), err)
-				return nil
-			}
-		}
+	// For equivalence hash to be formally correct, lists and maps
+	// in the equivalencePod should be normalized. (e.g. by sorting
+	// them) However, the vast majority of equivalent pod classes
+	// are expected to be created from a single pod template, so
+	// they will all have the same ordering.
+	return &equivalencePod{
+		Labels:         pod.Labels,
+		Affinity:       pod.Spec.Affinity,
+		Containers:     pod.Spec.Containers,
+		InitContainers: pod.Spec.InitContainers,
+		NodeName:       &pod.Spec.NodeName,
+		NodeSelector:   pod.Spec.NodeSelector,
+		Tolerations:    pod.Spec.Tolerations,
+		Volumes:        pod.Spec.Volumes,
 	}
-	return nil
 }
 
-// getPVCSet returns a set of PVC UIDs of given pod.
-func (e *EquivalencePodGenerator) getPVCSet(pod *v1.Pod) (sets.String, error) {
-	result := sets.NewString()
-	for _, volume := range pod.Spec.Volumes {
-		if volume.PersistentVolumeClaim == nil {
-			continue
-		}
-		pvcName := volume.PersistentVolumeClaim.ClaimName
-		pvc, err := e.pvcInfo.GetPersistentVolumeClaimInfo(pod.GetNamespace(), pvcName)
-		if err != nil {
-			return nil, err
-		}
-		result.Insert(string(pvc.UID))
-	}
-
-	return result, nil
-}
-
-// EquivalencePod is a group of pod attributes which can be reused as equivalence to schedule other pods.
-type EquivalencePod struct {
-	ControllerRef metav1.OwnerReference
-	PVCSet        sets.String
+// equivalencePod is a group of pod attributes which can be reused as equivalence to schedule other pods.
+type equivalencePod struct {
+	Labels         map[string]string
+	Affinity       *v1.Affinity
+	Containers     []v1.Container // note about ordering
+	InitContainers []v1.Container // note about ordering
+	NodeName       *string
+	NodeSelector   map[string]string
+	Tolerations    []v1.Toleration
+	Volumes        []v1.Volume // note about ordering
 }
 
 // portsConflict check whether existingPorts and wantPorts conflict with each other