See the comments here https://issues.apache.org/jira/browse/HBASE-22394
Although we claim that hbase 2.1.x can work together with hadoop 3.1.x, actually we require users to build the hbase binary with hadoop 3.1.x by their own if they really want to use hbase together with hadoop 3.1.x clients. The problem for HBASE-22394 is that our asyncfswal references some IA.Private classes and they have been changed between minor releases. It can be solved by using reflection. But in general, since hadoop also follows the semantic versioning, I do not think it is safe to do drop-in replacement between minor releases. So maybe a better way is to publish a hbase binary for each hadoop minor release line? Thanks.
