When running Samza in a clustered environment, I found that SamzaAppMaster jobs running on remote Yarn NodeManagers do not know how to properly contact the ResourceManager.
I have included a small patch that adds a directive to the YarnConfig to specify the hostname of the RM via "yarn.rm.hostname". I have tested this directive and it is working in my environment.
Please take a look at the patch and provide advise on whether this is the correct approach. If there is no better suggestion, i'd be happy to writeup some test cases to support the patch.