A YARN application created by a job. Application
information is a subset of
org.apache.hadoop.yarn.proto.YarnProtos.ApplicationReportProto.
Beta Feature: This report is available for testing purposes only. It
may be changed before final release.
Required. The application state.
Optional. The HTTP URL of the ApplicationMaster,
HistoryServer, or TimelineServer that provides application-
specific information. The URL uses the internal hostname, and
requires a proxy server for resolution and, possibly, access.