Critical Description
Reported by a new user on IRC who tried to set hbase.rootdir to file:///~/hbase, the master gets stuck and cannot be killed. I tried something similar on my machine and it spins while logging:
2011-12-09 16:11:17,002 WARN org.apache.hadoop.hbase.util.FSUtils: Unable to create version file at file:/bin/hbase, retrying: Mkdirs failed to create file:/bin/hbase
2011-12-09 16:11:27,002 WARN org.apache.hadoop.hbase.util.FSUtils: Unable to create version file at file:/bin/hbase, retrying: Mkdirs failed to create file:/bin/hbase
2011-12-09 16:11:37,003 WARN org.apache.hadoop.hbase.util.FSUtils: Unable to create version file at file:/bin/hbase, retrying: Mkdirs failed to create file:/bin/hbase
The reason it cannot be stopped is that the master's main thread is stuck in there and will never be notified:
"Master:0;su-jdcryans-01.local,51116,1323475535684" prio=5 tid=7f92b7a3c000 nid=0x1137ba000 waiting on condition [1137b9000]
java.lang.Thread.State: TIMED_WAITING (sleeping)
at java.lang.Thread.sleep(Native Method)
at org.apache.hadoop.hbase.util.FSUtils.setVersion(FSUtils.java:297)
at org.apache.hadoop.hbase.util.FSUtils.setVersion(FSUtils.java:268)
at org.apache.hadoop.hbase.master.MasterFileSystem.checkRootDir(MasterFileSystem.java:339)
at org.apache.hadoop.hbase.master.MasterFileSystem.createInitialFileSystemLayout(MasterFileSystem.java:128)
at org.apache.hadoop.hbase.master.MasterFileSystem.<init>(MasterFileSystem.java:113)
at org.apache.hadoop.hbase.master.HMaster.finishInitialization(HMaster.java:435)
at org.apache.hadoop.hbase.master.HMaster.run(HMaster.java:314)
at org.apache.hadoop.hbase.master.HMasterCommandLine$LocalHMaster.run(HMasterCommandLine.java:218)
at java.lang.Thread.run(Thread.java:680)
It seems we should do a better handling of the exceptions we get in there, and die if we need to. It would make a better user experience.
Maybe also do a check on hbase.rootdir before even starting the master.