版本問題的坑

半夜手賤，調整了下集羣配置，發現yarn掛了，nodemanager一直起不來，查了下log是個null pointer，沒看出來撒，結果google到這玩意。

https://issues.apache.org/jira/browse/YARN-2816

然後又看到這個

https://sskaje.me/2014/11/yarn-nodemanager-failed-start/

原來。。。

And, in the start-up message part,

2014-10-30 21:23:07,141 INFO org.apache.hadoop.yarn.server.nodemanager.NodeManager: registered UNIX signal handlers for [TERM, HUP, INT]
2014-10-30 21:23:08,259 INFO org.apache.hadoop.yarn.server.nodemanager.recovery.NMLeveldbStateStoreService: Using state database at /tmp/hadoop-yarn/yarn-nm-recovery/yarn-nm-state for recover
2014-10-30 21:23:08,291 INFO org.apache.hadoop.yarn.server.nodemanager.recovery.NMLeveldbStateStoreService$LeveldbLogger: Recovering log #432
2014-10-30 21:23:08,309 INFO org.apache.hadoop.yarn.server.nodemanager.recovery.NMLeveldbStateStoreService$LeveldbLogger: Delete type=0 #432
 
2014-10-30 21:23:08,309 INFO org.apache.hadoop.yarn.server.nodemanager.recovery.NMLeveldbStateStoreService$LeveldbLogger: Delete type=3 #431
 
2014-10-30 21:23:08,321 INFO org.apache.hadoop.yarn.server.nodemanager.recovery.NMLeveldbStateStoreService: Loaded NM state version info 1.0

The solution is, stop the instance, delete ‘/tmp/hadoop-yarn/’ from local filesystem, start the instance.

將每個namenode下的這個目錄都刪除後，終於恢復了，可以睡覺了。。。