Allow multiple host ports map to the same port in container

pkg/kubelet/dockertools/docker_test.go

@@ -698,6 +698,11 @@ func TestMakePortsAndBindings(t *testing.T) {
 			HostPort:      445,
 			Protocol:      "foobar",
 		},
+        {
+			ContainerPort: 443,
+			HostPort:      446,
+			Protocol:      "tcp",
+		},
 	}
 	exposedPorts, bindings := makePortsAndBindings(ports)
 	if len(ports) != len(exposedPorts) ||
@@ -734,6 +739,14 @@ func TestMakePortsAndBindings(t *testing.T) {
 			if value[0].HostIP != "" {
 				t.Errorf("Unexpected host IP: %s", value[0].HostIP)
 			}
+                case "446":
+			// allow multiple host ports bind to same container port
+			if !reflect.DeepEqual(docker.Port("443/tcp"), key) {
+				t.Errorf("Unexpected docker port: %#v", key)
+			}
+			if value[0].HostIP != "" {
+				t.Errorf("Unexpected host IP: %s", value[0].HostIP)
+			}
 		}
 	}
 }

pkg/kubelet/dockertools/manager.go

@@ -573,11 +573,21 @@ func makePortsAndBindings(portMappings []kubecontainer.PortMapping) (map[docker.
 		}
 		dockerPort := docker.Port(strconv.Itoa(interiorPort) + protocol)
 		exposedPorts[dockerPort] = struct{}{}
-		portBindings[dockerPort] = []docker.PortBinding{
-			{
-				HostPort: strconv.Itoa(exteriorPort),
-				HostIP:   port.HostIP,
-			},
+                
+        hostBinding := docker.PortBinding{
+			HostPort: strconv.Itoa(exteriorPort),
+			HostIP:   port.HostIP,
+		}
+
+		// Allow multiple host ports bind to same container port
+		if existedBindings := portBindings[dockerPort]; len(existedBindings) != 0 {
+			// If a container port already map to a host port, append to the host ports
+			portBindings[dockerPort] = append(existedBindings, hostBinding)
+		} else {
+			// Otherwise, it's fresh new port binding
+			portBindings[dockerPort] = []docker.PortBinding{
+				hostBinding,
+			}
 		}
 	}
 	return exposedPorts, portBindings