This occurs with Ambari 2.2.1 installing HDP 2.3. This error occurs when App Timeline Server tries to start unless the Yarn Property "yarn.timeline-service.store-class" is changed from "org.apache.hadoop.yarn.server.timeline.EntityGroupFSTimelineStore" to "org.apache.hadoop.yarn.server.timeline.LeveldbTimelineStore". Why and what can I do about it without having to change this property during the Ambari install? Here is the error: INFO service.AbstractService (AbstractService.java:noteFailure(272)) - Service org.apache.hadoop.yarn.server.applicationhistoryservice.ApplicationHistoryServer failed in state INITED; cause: java.lang.RuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class org.apache.hadoop.yarn.server.timeline.EntityGroupFSTimelineStore not found ... View more