The following features are shipped as part of HDP 2.2 HDFS, but are not supported:
NameNode Federation (HDFS-1052)
viewFS (HADOOP-7257)
The following Apache Components are shipped as part of HDP 2.2 YARN, but are not supported:
Fair Scheduler
MapReduce Uber AM
MapReduce Eclipse Plug-in
The following Apache Component is shipped as part of HDP 2.2 Kafka, but is not supported:
Delete Topic
