Accessing Pod through kubedns without expose as service

I am trying to test inter-pod communication without expose as service. I have read that a pod does have FQDN in kubedns. kubernetes doc

Its default should be (A Record)
metadata_name.namespace.svc.cluster.local
or
hostname.subdomain.namespace.svc.cluster.local

But I tried both with curl and nslookup. All failed. The service is healthy, I could curl it with pod IP (172.17.0.5)

curl: (6) could not resolve host
nslookup: can't resolve '(null)': Name does not resolved

What am I missing?

Solution

I suggest adding a service with type ClusterIP for this: https://kubernetes.io/docs/concepts/services-networking/service/#publishing-services-service-types

kind: Service
apiVersion: v1
metadata:
  name: my-service
spec:
  selector:
    app: MyApp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  type: ClusterIP

It does not expose your pod outside the cluster. Note that this is default service type and you can omit specifying it.

Then query the serivce like:

curl http://my-service.namespace.svc.cluster.local

This approach is better than using pod DNS directly for 2 reasons:

you don't need to know the exact pod name (e.g. name-id)
in this case you can run multiple pods behind the service and it will load-balance requests. Or just run one and it does exactly what you want.