I use istio-ingress gateway and virtualservice to expose different microservices. So far all of them have been http services, so it was straight-forward to follow istio's documentation.

But with kafka I am facing some issues. I am using bitnami/kafka helm chart for kafka installation. Here's the values.yaml used for it:

global:
  storageClass: "kafka-sc"

replicaCount: 3
deleteTopicEnable: true

resources:
  requests:
    memory: 1024Mi
    cpu: 500m
  limits:
    memory: 2048Mi
    cpu: 1000m

zookeeper:
  replicaCount: 3
  resources:
    requests:
      memory: 1024Mi
      cpu: 500m
    limits:
      memory: 2048Mi
      cpu: 1000m

This deployment exposes kafka on this endpoint: my-kafka.kafka.svc.cluster.local:9092

I want this endpoint to be accessible via internet using ingress controller. Therefore, I applied following kubernetes manifests -->

A. kafka-ingress-gateway.yaml

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: kafka-ingress-gateway
  namespace: kafka
spec:
  selector:
    istio: ingressgateway
  servers:
  - port:
      number: 9092
      name: tcp
      protocol: TCP
    hosts:
    - "kafka.<public_domain>"

B. kafka-ingress-virtualservice.yaml

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: kafka-ingress-virtualservice
  namespace: kafka
spec:
  hosts:
  - "kafka.<public_domain>"
  gateways:
  - kafka/kafka-ingress-gateway
  tcp:
  - match:
    - port: 9092
    route:
    - destination:
        host: my-kafka.kafka.svc.cluster.local
        port:
          number: 9092

To verify whether this works, I am using following approach:

1. Create a kafka-client pod and login to it in two different terminals
2. In first terminal, I produce in a topic called test using this command: kafka-console-producer.sh --broker-list my-kafka-0.my-kafka-headless.kafka.svc.cluster.local:9092 --topic test

3. In second terminal, I consume in test topic using this command.

In here, this works: kafka-console-consumer.sh --bootstrap-server my-kafka.kafka.svc.cluster.local:9092 --topic test --from-beginning

This does not work: kafka-console-consumer.sh --bootstrap-server kafka.<public_domain>:9092 --topic test --from-beginning

I am getting this error: WARN [Consumer clientId=consumer-console-consumer-89304-1, groupId=console-consumer-89304] Bootstrap broker kafka.<public_domain>:9092 (id: -1 rack: null) disconnected (org.apache.kafka.clients.NetworkClient)

I am new to kafka, so not sure what else is required to expose the consumer endpoint. From similar questions on stackoverflow, I noticed we are supposed to define "advertisedListeners" in kafka config, but not sure what value to put there.

Please let me know if I am missing any details here.