Services, as defined by the Service API, allow for a basic level of Layer 3/4 load balancing.

Ingress is the most useful if you want to expose multiple services under the same IP address, and these services all use the same L7 protocol (typically HTTP).

If ingress controller routes request to service itself and service allows a basic level Layer3/4 round robin load balancing to pods , where is Layer 7 load balancing here ? It is just layer 7 for routing not load balancing, right?

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
   ingress.kubernetes.io/rewrite-target: /
 name: web-ingress
spec:
  rules:
  - host: kubernetes.foo.bar
    http:
      paths:
      - backend:
          serviceName: appsvc
          servicePort: 80
        path: /app