Hey everyone! We have started seeing test failures in YARN PRs for a while. We have identified the problematic commit, which is HADOOP-18082 <https://issues.apache.org/jira/browse/HADOOP-18082>, however, this change just revealed the race condition lying in ProtobufRpcEngine2 introduced in HADOOP-17046 <https://issues.apache.org/jira/browse/HADOOP-17046>. We have also fixed the underlying issue via a locking mechanism, presented in HADOOP-18143 <https://issues.apache.org/jira/browse/HADOOP-18143>, but since it is out of our area of expertise, we can neither verify nor guarantee that it will not cause some subtle issues in the RPC system. As we think it is a core part of Hadoop, we would use feedback from someone who is proficient in this part.
Regards: Andras
