nodePortAllocated = metrics.NewGauge(
		&metrics.GaugeOpts{
			Namespace:      namespace,
			Subsystem:      subsystem,
			Name:           "allocated_ports",
			Help:           "Gauge measuring the number of allocated NodePorts for Services",
			StabilityLevel: metrics.ALPHA,
		},
	)
	// nodePortAvailable indicates the amount of ports available by NodePort Service.

		// If no ports are already being allocated by this operation,
		// then choose a sensible guess for a dummy port number
		var lastPort int
		for _, allocatedPort := range op.allocated {
			if allocatedPort > lastPort {
				lastPort = allocatedPort
			}
		}
		if len(op.allocated) == 0 {
			lastPort = 32768
		}

		// Try to find the next non allocated port.

		return
	}
	// for testing.
	if s.statusPort == 0 {
		_, hostPort, _ := net.SplitHostPort(l.Addr().String())
		allocatedPort, _ := strconv.Atoi(hostPort)
		s.mutex.Lock()
		s.statusPort = uint16(allocatedPort)
		s.mutex.Unlock()
	}
	defer l.Close()

	go func() {
		if err := http.Serve(l, mux); err != nil {
			if network.IsUnexpectedListenerError(err) {