es-data should start only after es-master has started

[charlesverdad]

There should be a way to deploy everything by just using the kubectl apply -f . command without having to worry about the sequence in which the containers are deployed. That way when running in minikube locally, restarting the local machine should not cause issues.

This could be done by maybe adding a readiness probe to es-master and making es-data listen to that somehow, delaying its "entrypoint" until the master is ready. Or maybe add an init container which will sleep until the es-master is "ping-able". There's also the option of adding a Pod lifecycle hook to only run es-data on es-master's postStart.

[pires]

Open to review PRs.