what's the difference between openshift route and k8s ingress?

Ultimately they are intended to achieve the same end. Originally Kubernetes had no such concept and so in OpenShift the concept of a Route was developed, along with the bits for providing a load balancing proxy etc. In time it was seen as being useful to have something like this in Kubernetes, so using Route from OpenShift as a starting point for what could be done, Ingress was developed for Kubernetes. In the Ingress version they went for a more generic rules based system so how you specify them looks different, but the intent is to effectively be able to do the same thing.

The following code implementation will create a route in OCP. The OCP will consider the ingress as a route in the same way.

// build the ingress/route objectfunc (r *ReconcileMobileSecurityService) buildAppIngress(m *mobilesecurityservicev1alpha1.MobileSecurityService) *v1beta1.Ingress {    ls := getAppLabels(m.Name)    hostName := m.Name + "-" + m.Namespace + "." + m.Spec.ClusterHost + ".nip.io"    ing := &v1beta1.Ingress{        TypeMeta: v1.TypeMeta{            APIVersion: "extensions/v1beta1",            Kind:       "Ingress",        },        ObjectMeta: v1.ObjectMeta{            Name:      m.Name,            Namespace: m.Namespace,            Labels:    ls,        },        Spec: v1beta1.IngressSpec{            Backend: &v1beta1.IngressBackend{                ServiceName: m.Name,                ServicePort: intstr.FromInt(int(m.Spec.Port)),            },            Rules: []v1beta1.IngressRule{                {                    Host: hostName,                    IngressRuleValue: v1beta1.IngressRuleValue{                        HTTP: &v1beta1.HTTPIngressRuleValue{                            Paths: []v1beta1.HTTPIngressPath{                                {                                    Backend: v1beta1.IngressBackend{                                        ServiceName: m.Name,                                        ServicePort: intstr.FromInt(int(m.Spec.Port)),                                    },                                    Path: "/",                                },                            },                        },                    },                },            },        },    }    // Set MobileSecurityService instance as the owner and controller    controllerutil.SetControllerReference(m, ing, r.scheme)    return ing}