Hi, Hope this hasn't been asked before.
I'm interested in finding out more about Hadoop RPC and how it works. I'd like to write a service that cleanly fits into the ecosystem and making use of the Hadoop RPC library looks like a good start, particularly as my service will be called (at least) once for each mapper. I've found this page: https://wiki.apache.org/hadoop/HadoopRpc I've followed the code-snippets and gotten a simple client / server app working. There's not a huge amount of documentation available, but from: http://hortonworks.com/blog/rpc-improvements-and-wire-compatibility-in-apache-hadoop/ it sounds like Hadoop has migrated from the original RPC over-the-wire serialization to use Google Protobufs. Does that mean that the approach documented in the first link is deprecated (or soon to be), or that there's a better approach? Or is it just the on-the-wire serialization that's changed? Also interested in how authentication works on a secure cluster. Is this provided 'for free' as part of the RPC library? That first link refers to a follow up post regarding authentication, but I can't find it anyway. Many thanks, Tom
