Hi, I'm currently working on https://issues.apache.org/jira/browse/FLINK-1605 and its a hell of a mess.
I got almost everything working, except for the hadoop 2.0.0-alpha profile. The profile exists because google protobuf has a different version in that Hadoop release. Since maven is setting the version of protobuf for the entire project to the older version, we have to use an older akka version which is causing issues. The logical conclusion from that would be shading Hadoop's protobuf version into the Hadoop jars. That by itself is working, however its not working for the "flink-yarn-tests". I think I can also solve the issue with the flink-yarn-tests, but it would be a very dirty hack (either injecting shaded code into the failsafe tests-classpath or putting test code into src/main). But the general question remains: Are we willing to continue spending a lot of time on maintaining the profile? Till has spend a lot of time recently to fix failing testcases for that old akka version, I spend almost two days now on getting the shading/dependencies right, and I'm sure we'll keep having troubles with the profile. Therefore, I was wondering if this is the right time to drop support for CDH4 / Hadoop 2.0.0-alpha. Best, Robert