I got it working!!! The answer is to create a config map with use-proxy-protocol: “true” as follows:
Step 1. Follow instructions from the tutorial
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/mandatory.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/provider/cloud-generic.yaml
Step 2. Create the following configmap.yaml that includes use-proxy-protocol:
# configmap.yaml
---
apiVersion: v1
kind: ConfigMap
metadata:
name: nginx-configuration
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
data:
use-forwarded-headers: "true"
compute-full-forwarded-for: "true"
use-proxy-protocol: "true"
Step 3. Apply configmap.yaml
kubectl apply -f configmap.yaml
Step 4. Create your ingress resource:
# ingress.yaml
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: echo-ingress
spec:
rules:
- host: echo1.example.com
http:
paths:
- backend:
serviceName: echo1
servicePort: 80
- host: echo2.example.com
http:
paths:
- backend:
serviceName: echo2
servicePort: 80
Step 5. Apply your ingress resource:
kubectl apply -f ingress.yaml
Step 6. Wait for the External IP of your load balancer
kubectl get svc -n ingress-nginx
Step 7. Enable Proxy Protocol on your load balancer

Step 8. Update your DNS A records with your External IP
Best of luck …

by Hanif Jetha
In this tutorial, learn how to set up and secure an Nginx Ingress Controller with Cert-Manager on DigitalOcean Kubernetes.
Can you help me for reverse proxy?
From: http://localhost/api/apps/v1/*
to : http://localhost/v1/*?