Protocol: string("UDP"),
	}
	err = fake.AddVirtualServer(vs2)
	if err != nil {
		t.Errorf("Unexpected error when add virtual server, error: %v", err)
	}
	// Add another virtual server
	vs3 := &utilipvs.VirtualServer{
		Address:  netutils.ParseIPSloppy("10::40"),
		Port:     uint16(7777),
		Protocol: string("SCTP"),
	}
	err = fake.AddVirtualServer(vs3)
	if err != nil {

type Interface interface {
	// Flush clears all virtual servers in system. return occurred error immediately.
	Flush() error
	// AddVirtualServer creates the specified virtual server.
	AddVirtualServer(*VirtualServer) error
	// UpdateVirtualServer updates an already existing virtual server.  If the virtual server does not exist, return error.
	UpdateVirtualServer(*VirtualServer) error

}

func toRealServerKey(rs *utilipvs.RealServer) *RealServerKey {
	return &RealServerKey{
		Address: rs.Address,
		Port:    rs.Port,
	}
}

// AddVirtualServer is a fake implementation, it simply adds the VirtualServer into the cache store.
func (f *FakeIPVS) AddVirtualServer(serv *utilipvs.VirtualServer) error {
	if serv == nil {
		return fmt.Errorf("failed to add virtual server, error: virtual server can't be nil")
	}

	if err != nil {
		klog.ErrorS(err, "IPVS interface can't be initialized")
		return nil
	}
	return &runner{
		ipvsHandle: handle,
	}
}

// AddVirtualServer is part of ipvs.Interface.
func (runner *runner) AddVirtualServer(vs *VirtualServer) error {
	svc, err := toIPVSService(vs)
	if err != nil {
		return fmt.Errorf("could not convert local virtual server to IPVS service: %w", err)
	}
	runner.mu.Lock()

// fakeIpvs implements utilipvs.Interface
type fakeIpvs struct {
	ipvsErr   string
	vsCreated bool
}

func (f *fakeIpvs) Flush() error {
	return nil
}
func (f *fakeIpvs) AddVirtualServer(*utilipvs.VirtualServer) error {
	if f.ipvsErr == "AddVirtualServer" {
		return fmt.Errorf("oops")
	}
	f.vsCreated = true
	return nil
}
func (f *fakeIpvs) UpdateVirtualServer(*utilipvs.VirtualServer) error {
	return nil
}

	logger := klog.FromContext(ctx)
	// BUG: https://github.com/moby/ipvs/issues/27
	// If ipvs is not compiled into the kernel no error is returned and handle==nil.
	// This in turn causes ipvs.GetVirtualServers and ipvs.AddVirtualServer
	// to return ok (err==nil). If/when this bug is fixed parameter "ipvs" will be nil
	// if ipvs is not supported by the kernel. Until then a re-read work-around is used.
	if ipvs == nil {