Added events for failures in PV/PVC processing:

- PV has a dangling reference to a PVC
- PVC is trying to bind to a PV that already references a different PVC

Change-Id: Ic509d39808763149b02b4dd52347edb74a8803fd

Author: yuga711

pkg/controller/volume/persistentvolume/pv_controller.go

@@ -415,6 +415,8 @@ func (ctrl *PersistentVolumeController) syncUnboundClaim(claim *v1.PersistentVol
 				// OBSERVATION: pvc is "Pending", pv is "Bound"
 				if !metav1.HasAnnotation(claim.ObjectMeta, pvutil.AnnBoundByController) {
 					klog.V(4).Infof("synchronizing unbound PersistentVolumeClaim[%s]: volume already bound to different claim by user, will retry later", claimToClaimKey(claim))
+					claimMsg := fmt.Sprintf("volume %q already bound to a different claim.", volume.Name)
+					ctrl.eventRecorder.Event(claim, v1.EventTypeWarning, events.FailedBinding, claimMsg)
 					// User asked for a specific PV, retry later
 					if _, err = ctrl.updateClaimStatus(claim, v1.ClaimPending, nil); err != nil {
 						return err
@@ -424,6 +426,9 @@ func (ctrl *PersistentVolumeController) syncUnboundClaim(claim *v1.PersistentVol
 					// This should never happen because someone had to remove
 					// AnnBindCompleted annotation on the claim.
 					klog.V(4).Infof("synchronizing unbound PersistentVolumeClaim[%s]: volume already bound to different claim %q by controller, THIS SHOULD NEVER HAPPEN", claimToClaimKey(claim), claimrefToClaimKey(volume.Spec.ClaimRef))
+					claimMsg := fmt.Sprintf("volume %q already bound to a different claim.", volume.Name)
+					ctrl.eventRecorder.Event(claim, v1.EventTypeWarning, events.FailedBinding, claimMsg)
+
 					return fmt.Errorf("Invalid binding of claim %q to volume %q: volume already claimed by %q", claimToClaimKey(claim), claim.Spec.VolumeName, claimrefToClaimKey(volume.Spec.ClaimRef))
 				}
 			}
@@ -604,12 +609,15 @@ func (ctrl *PersistentVolumeController) syncVolume(volume *v1.PersistentVolume)
 					return err
 				}
 			}
-
 			if err = ctrl.reclaimVolume(volume); err != nil {
 				// Release failed, we will fall back into the same condition
 				// in the next call to this method
 				return err
 			}
+			if volume.Spec.PersistentVolumeReclaimPolicy == v1.PersistentVolumeReclaimRetain {
+				// volume is being retained, it references a claim that does not exist now.
+				klog.V(4).Infof("PersistentVolume[%s] references a claim %q (%s) that is not found", volume.Name, claimrefToClaimKey(volume.Spec.ClaimRef), volume.Spec.ClaimRef.UID)
+			}
 			return nil
 		} else if claim.Spec.VolumeName == "" {
 			if pvutil.CheckVolumeModeMismatches(&claim.Spec, &volume.Spec) {