Don't wrongly identify endpoint addresses only due to equal IP

Before this patch the endpoint IP was used to identify endpoint addresses. This
leads to wrong unification of endpoints of different pods having the same IP (e.g.
non container IP in case of Mesos). This patch takes the EndpointAddress.targetRef.UID
into consideration as well.

pkg/api/endpoints/util.go

@@ -24,6 +24,7 @@ import (
 	"sort"
 
 	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/types"
 	"k8s.io/kubernetes/pkg/util"
 )
 
@@ -33,31 +34,35 @@ import (
 // form for things like comparison.  The result is a newly allocated slice.
 func RepackSubsets(subsets []api.EndpointSubset) []api.EndpointSubset {
 	// First map each unique port definition to the sets of hosts that
-	// offer it.  The sets of hosts must be de-duped, using IP as the key.
-	type ipString string
-	allAddrs := map[ipString]*api.EndpointAddress{}
+	// offer it.  The sets of hosts must be de-duped, using IP+UID as the key.
+	type addressKey struct {
+		ip string
+		uid types.UID
+	}
+	allAddrs := map[addressKey]*api.EndpointAddress{}
 	portsToAddrs := map[api.EndpointPort]addressSet{}
 	for i := range subsets {
 		for j := range subsets[i].Ports {
 			epp := &subsets[i].Ports[j]
 			for k := range subsets[i].Addresses {
 				epa := &subsets[i].Addresses[k]
-				ipstr := ipString(epa.IP)
-				// Accumulate the most "complete" address we can.
-				if allAddrs[ipstr] == nil {
+				ak := addressKey{ip: epa.IP}
+				if epa.TargetRef != nil {
+					ak.uid = epa.TargetRef.UID
+				}
+				// Accumulate the address.
+				if allAddrs[ak] == nil {
 					// Make a copy so we don't write to the
 					// input args of this function.
 					p := &api.EndpointAddress{}
 					*p = *epa
-					allAddrs[ipstr] = p
-				} else if allAddrs[ipstr].TargetRef == nil {
-					allAddrs[ipstr].TargetRef = epa.TargetRef
+					allAddrs[ak] = p
 				}
 				// Remember that this port maps to this address.
 				if _, found := portsToAddrs[*epp]; !found {
 					portsToAddrs[*epp] = addressSet{}
 				}
-				portsToAddrs[*epp].Insert(allAddrs[ipstr])
+				portsToAddrs[*epp].Insert(allAddrs[ak])
 			}
 		}
 	}
@@ -104,18 +109,32 @@ func hashAddresses(addrs addressSet) string {
 	for k := range addrs {
 		slice = append(slice, k)
 	}
-	sort.Sort(addrPtrsByIP(slice))
+	sort.Sort(addrPtrsByIpAndUID(slice))
 	hasher := md5.New()
 	util.DeepHashObject(hasher, slice)
 	return hex.EncodeToString(hasher.Sum(nil)[0:])
 }
 
-type addrPtrsByIP []*api.EndpointAddress
+func LessEndpointAddress(a, b *api.EndpointAddress) bool {
+	ipComparison := bytes.Compare([]byte(a.IP), []byte(b.IP))
+	if ipComparison != 0 {
+		return ipComparison < 0
+	}
+	if (b.TargetRef == nil) {
+		return false
+	}
+	if (a.TargetRef == nil) {
+		return true
+	}
+	return a.TargetRef.UID < b.TargetRef.UID
+}
 
-func (sl addrPtrsByIP) Len() int      { return len(sl) }
-func (sl addrPtrsByIP) Swap(i, j int) { sl[i], sl[j] = sl[j], sl[i] }
-func (sl addrPtrsByIP) Less(i, j int) bool {
-	return bytes.Compare([]byte(sl[i].IP), []byte(sl[j].IP)) < 0
+type addrPtrsByIpAndUID []*api.EndpointAddress
+
+func (sl addrPtrsByIpAndUID) Len() int      { return len(sl) }
+func (sl addrPtrsByIpAndUID) Swap(i, j int) { sl[i], sl[j] = sl[j], sl[i] }
+func (sl addrPtrsByIpAndUID) Less(i, j int) bool {
+	return LessEndpointAddress(sl[i], sl[j])
 }
 
 // SortSubsets sorts an array of EndpointSubset objects in place.  For ease of
@@ -123,7 +142,7 @@ func (sl addrPtrsByIP) Less(i, j int) bool {
 func SortSubsets(subsets []api.EndpointSubset) []api.EndpointSubset {
 	for i := range subsets {
 		ss := &subsets[i]
-		sort.Sort(addrsByIP(ss.Addresses))
+		sort.Sort(addrsByIpAndUID(ss.Addresses))
 		sort.Sort(portsByHash(ss.Ports))
 	}
 	sort.Sort(subsetsByHash(subsets))
@@ -146,12 +165,12 @@ func (sl subsetsByHash) Less(i, j int) bool {
 	return bytes.Compare(h1, h2) < 0
 }
 
-type addrsByIP []api.EndpointAddress
+type addrsByIpAndUID []api.EndpointAddress
 
-func (sl addrsByIP) Len() int      { return len(sl) }
-func (sl addrsByIP) Swap(i, j int) { sl[i], sl[j] = sl[j], sl[i] }
-func (sl addrsByIP) Less(i, j int) bool {
-	return bytes.Compare([]byte(sl[i].IP), []byte(sl[j].IP)) < 0
+func (sl addrsByIpAndUID) Len() int      { return len(sl) }
+func (sl addrsByIpAndUID) Swap(i, j int) { sl[i], sl[j] = sl[j], sl[i] }
+func (sl addrsByIpAndUID) Less(i, j int) bool {
+	return LessEndpointAddress(&sl[i], &sl[j])
 }
 
 type portsByHash []api.EndpointPort