Tip on debugging clients from 0.91 snapshots talking to 0.92 RC

[Jean-Daniel Cryans <jd...@apache.org>]

Hey guys,

I was helping out a user on IRC that was trying to use Hush (from
Lars's book https://github.com/larsgeorge/hbase-book/tree/master/hush)
and he was seeing this:

INFO [main] (HConnectionManager.java:596) - getMaster attempt 0 of 10
failed; retrying after sleep of 1000
java.net.UnknownHostException: unknown host:
?4130@hbase-dev001.krxd.netip-10-85-115-86.ec2.internal
	at org.apache.hadoop.hbase.ipc.HBaseClient$Connection.<init>(HBaseClient.java:224)
	at org.apache.hadoop.hbase.ipc.HBaseClient.getConnection(HBaseClient.java:954)
	at org.apache.hadoop.hbase.ipc.HBaseClient.call(HBaseClient.java:816)
	at org.apache.hadoop.hbase.ipc.WritableRpcEngine$Invoker.invoke(WritableRpcEngine.java:141)
	at $Proxy4.getProtocolVersion(Unknown Source)
	at org.apache.hadoop.hbase.ipc.WritableRpcEngine.getProxy(WritableRpcEngine.java:174)
	at org.apache.hadoop.hbase.ipc.HBaseRPC.getProxy(HBaseRPC.java:295)
	at org.apache.hadoop.hbase.ipc.HBaseRPC.getProxy(HBaseRPC.java:272)
	at org.apache.hadoop.hbase.ipc.HBaseRPC.getProxy(HBaseRPC.java:324)
	at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getMaster(HConnectionManager.java:579)
	at org.apache.hadoop.hbase.client.HBaseAdmin.<init>(HBaseAdmin.java:94)
	at com.hbasebook.hush.schema.SchemaManager.process(SchemaManager.java:126)
	at com.hbasebook.hush.HushMain.main(HushMain.java:57)

So what you can read in there is that the master address is a
concatenation of a pid, @, a hostname and then another hostname. Took
me while to figure out that RecoverableZooKeeper now prepends an id to
every piece of data written to ZK and so I thought that we inserted
the master's hostname twice.

Finally I saw it and understood that the user left the hbase-0.91 jar
in Hush and that the server was on 0.92. Once he shuffled the jars
around it worked.

Hope this will help someone,

J-D