Author: Reynold Xin <rxin@apache.org> Closes #1260 from rxin/signalhandler1 and squashes the following commits: 8e73552 [Reynold Xin] Uh add Logging back in ApplicationMaster. 0402ba8 [Reynold Xin] Synchronize SignalLogger.register. dc70705 [Reynold Xin] Added SignalLogger to YARN ApplicationMaster. 79a21b4 [Reynold Xin] Added license header. 0da052c [Reynold Xin] Added the SignalLogger itself. e587d2e [Reynold Xin] [SPARK-2318] When exiting on a signal, print the signal name first.
Hadoop Yarn related codes are organized in separate directories to minimize duplicated code.
common : Common codes that do not depending on specific version of Hadoop.
alpha / stable : Codes that involve specific version of Hadoop YARN API.
alpha represents 0.23 and 2.0.x stable represents 2.2 and later, until the API changes again.
alpha / stable will build together with common dir into a single jar