Hi with regards to IIGD and Gateway, they use labels, just like how a Service connects to Deployment using matching labels

See the bold selectors below:

For Gateway:

apiVersion: networking.istio.io/v1alpha3

kind: Gateway

metadata:

name: mymicroservices-gateway

namespace: mymicroservices

spec:

selector:

istio: ingressgateway

For Deployment:

NOTE: This manifest is not shown in the article since we directly installed istio-ingressgateway via helm from Part I step 6.

apiVersion: apps/v1

kind: Deployment

metadata:

name: istio-ingressgateway

namespace: istio-ingress

spec:

selector:

matchLabels:

istio: ingressgateway

I hope this answers your question. Thank you for the response :)