I am trying to setup connection to my databases which reside outside of GKE cluster from within the cluster.

I have read various tutorials including https://cloud.google.com/blog/products/gcp/kubernetes-best-practices-mapping-external-services and multiple SO questions though the problem persists.

Here is an example configuration with which I am trying to setup kafka connectivity:

---
kind: Endpoints
apiVersion: v1
metadata:
  name: kafka
subsets:
  - addresses:
      - ip: 10.132.0.5
    ports:
      - port: 9092

---
kind: Service
apiVersion: v1
metadata:
  name: kafka
spec:
  type: ClusterIP
  ports:
  - port: 9092
    targetPort: 9092

I am able to get some sort of response by connecting directly via nc 10.132.0.5 9092 from the node VM itself, but if I create a pod, say by kubectl run -it --rm --restart=Never alpine --image=alpine sh then I am unable to connect from within the pod using nc kafka 9092. All libraries in my code fail by timing out so it seems to be some kind of routing issue.

Kafka is given as an example, I am having the same issues connecting to other databases as well.