[WIP][SPARK-20629][CORE] Copy shuffle data when nodes are being shutdown#28331

holdenk wants to merge 32 commits into

apache:masterapache/spark:masterfrom

holdenk:SPARK-20629-copy-shuffle-data-when-nodes-are-being-shutdown-flatholdenk/spark:SPARK-20629-copy-shuffle-data-when-nodes-are-being-shutdown-flatCopy head branch name to clipboard