Expose services via Istio ingress gateway - kubernetes

Question

I am new to istio and I want to expose three services and route traffic to those services based on the port number passed to "website.com:port" or subdomain.
services deployment config files:
apiVersion: v1
kind: Service
metadata:
name: visitor-service
labels:
app: visitor-service
spec:
ports:
- port: 8000
nodePort: 30800
targetPort: 8000
selector:
app: visitor-service
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: visitor-service
spec:
replicas: 1
selector:
matchLabels:
app: visitor-service
template:
metadata:
labels:
app: visitor-service
spec:
containers:
- name: visitor-service
image: visitor-service
ports:
- containerPort: 8000
second service:
apiVersion: v1
kind: Service
metadata:
name: auth-service
labels:
app: auth-service
spec:
ports:
- port: 3004
nodePort: 30304
targetPort: 3004
selector:
app: auth-service
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: auth-service
spec:
replicas: 1
selector:
matchLabels:
app: auth-service
template:
metadata:
labels:
app: auth-service
spec:
containers:
- name: auth-service
image: auth-service
ports:
- containerPort: 3004
Third one:
apiVersion: v1
kind: Service
metadata:
name: gateway
labels:
app: gateway
spec:
ports:
- port: 8080
nodePort: 30808
targetPort: 8080
selector:
app: gateway
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: gateway
spec:
replicas: 1
selector:
matchLabels:
app: gateway
template:
metadata:
labels:
app: gateway
spec:
containers:
- name: gateway
image: gateway
ports:
- containerPort: 8080
If someone can help setting up the gateway and virtual service configuration it would be great.

Answer 1

It seems like you simply want to expose your applications, for that reason istio seems like a total overkill since it comes with a lot of overhead that you won't be using.
Regardless of whether you want to use istio as your default ingress or any other ingress-controller (nginx, traefik, ...) the following construct applies to all of them:
Expose the ingress-controller via a service of type NodePort or LoadBalancer, depending on your infrastructure. In a cloud environment the latter one will most likely work the best for you (if on GKE, AKS, EKS, ...).
Once it is exposed set up a DNS A record to point to the external IP address. Afterwards you can start configuring your ingress, depending on which ingress-controller you chose the following YAML may need some adjustments (example is given for istio):
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: istio
name: ingress
spec:
rules:
- host: httpbin.example.com
http:
paths:
- path: /
pathType: Prefix
backend:
serviceName: httpbin
servicePort: 8000
If a request for something like httpbin.example.com comes in to your ingress-controller it is going to send the request to a service named httpbin on port 8000.
As can be seen in the YAML posted above, the rules and paths field take a list (indicated by the - in the next line). To expose multiple services simply add a new entry to the list, e.g.:
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: istio
name: ingress
spec:
rules:
- host: httpbin.example.com
http:
paths:
- path: /httpbin
pathType: Prefix
backend:
serviceName: httpbin
servicePort: 8000
- path: /apache
pathType: Prefix
backend:
serviceName: apache
servicePort: 8080
This is going to send requests like httpbin.example.com/httpbin/ to httpbin and httpbin.example.com/apache/ to apache.
For further information see:
https://istio.io/latest/docs/tasks/traffic-management/ingress/kubernetes-ingress/
https://kubernetes.io/docs/concepts/services-networking/ingress/