newIngress.Spec.DefaultBackend = &networking.IngressBackend{
					Resource: resourceBackend}
			},
			expectedErrs: field.ErrorList{},
		},
		"old DefaultBackend.Resource allowed on update": {
			tweakIngresses: func(newIngress, oldIngress *networking.Ingress) {
				oldIngress.Spec.DefaultBackend = &networking.IngressBackend{
					Resource: resourceBackend}

	// Backend defines the referenced service endpoint to which the traffic
	// will be forwarded to.
	Backend IngressBackend `json:"backend" protobuf:"bytes,2,opt,name=backend"`
}

// IngressBackend describes all endpoints for a given service and port.
type IngressBackend struct {
	// Specifies the name of the referenced service.
	// +optional