Bootstrap server issue: Accessing Kafka cluster in a client Java Application

[talhagithub02]

Hi every1,
I need your assistance as I am stuck in to this:
I am running Skrimzi on Windows pc with Docker desktop Kubernetes on my local pc. I am able to create cluster (configuration image attached) and it is in healthy state , I can send data to a topic and see in producer, but when I am trying to access that cluster using Java , it is not recognizing the bootstrap server (Error: No resolvable bootstrap urls given in bootstrap.servers). Here is what I have tried:

1. using this command "kubectl get services -n kafka" i got the name of the bootstrap server "my-cluster-kafka-bootstrap" but when i am passing this in to Java

`String bootstrapServers = "my-cluster-kafka-external-bootstrap:9094";

    // Create AdminClient properties
    java.util.Properties properties = new java.util.Properties();
    properties.put(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);`

I am receiving the unresolvable bootstrap error.

2. I tried adjusting config file to include

listeners: - name: external port: 9094 type: nodeport tls: true

and tried using docker ip "192.168.65.3" with this Port , still same issue.

I tired many other ways but bounding this to only these two,

One thing to mention is I came across this recent consumer blog: https://strimzi.io/blog/2023/11/09/kafka-consumer-client-essentials/

which mentions to get bootstrap server from this command:
kubectl get kafka <kafka_cluster_name> -o=jsonpath='{.status.listeners[*].bootstrapServers}{"\n"}' but this is returning me Nothing.

Any output you need from myside, I can provide, I need to access the cluster inside Java application on my local.

[scholzj]

I do not have Windows, so it is hard to say how exactly it works there. Node ports typically work for example on Minikube run with VM driver (as a virtual machine). But it typically does not work with Kubernetes running inside of a Docker container inside a VM as the Kubernetes worker node is in a different network. You can check this blog post series to better understand how it works: https://strimzi.io/blog/2019/04/17/accessing-kafka-part-1/. You could also try this project I created: https://github.com/scholzj/kekspose (but as I said, I do not have Windows, so never had a chance to test it there)