Revert "Change equivalence class hashing function"

pkg/scheduler/algorithm/predicates/utils.go

@@ -17,8 +17,12 @@ 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"
 )
 
@@ -66,6 +70,68 @@ func CreateSelectorFromLabels(aL map[string]string) labels.Selector {
 	return labels.Set(aL).AsSelector()
 }
 
+// EquivalencePodGenerator is a generator of equivalence class for pod with consideration of PVC info.
+type EquivalencePodGenerator struct {
+	pvcInfo PersistentVolumeClaimInfo
+}
+
+// NewEquivalencePodGenerator returns a getEquivalencePod method with consideration of PVC info.
+func NewEquivalencePodGenerator(pvcInfo PersistentVolumeClaimInfo) algorithm.GetEquivalencePodFunc {
+	g := &EquivalencePodGenerator{
+		pvcInfo: pvcInfo,
+	}
+	return g.getEquivalencePod
+}
+
+// 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
+			}
+		}
+	}
+	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
+}
+
 // portsConflict check whether existingPorts and wantPorts conflict with each other
 // return true if we have a conflict
 func portsConflict(existingPorts schedutil.HostPortInfo, wantPorts []*v1.ContainerPort) bool {