How do I un-expose (undo expose) service?
Assuming you have a deployment called hello-world, and do a kubectl expose as follows:
kubectl expose deployment hello-world --type=ClusterIP --name=my-service
this will create a service called my-service, which makes your deployment accessible for debugging, as you described.
To display information about the Service:
kubectl get services my-service
To delete this service when you are done debugging:
kubectl delete service my-service
Now your deployment is un-exposed.