log error when error occur in CleanupLeftovers()

pkg/proxy/ipvs/proxier.go

@@ -806,6 +806,7 @@ func CleanupLeftovers(ipvs utilipvs.Interface, ipt utiliptables.Interface, ipset
 		encounteredError = false
 		err := ipvs.Flush()
 		if err != nil {
+			glog.Errorf("Error flushing IPVS rules: %v", err)
 			encounteredError = true
 		}
 	}
@@ -813,6 +814,7 @@ func CleanupLeftovers(ipvs utilipvs.Interface, ipt utiliptables.Interface, ipset
 	nl := NewNetLinkHandle()
 	err := nl.DeleteDummyDevice(DefaultDummyDevice)
 	if err != nil {
+		glog.Errorf("Error deleting dummy device %s created by IPVS proxier: %v", DefaultDummyDevice, err)
 		encounteredError = true
 	}
 	// Clear iptables created by ipvs Proxier.