Hadoop version support matrix, hadoop Hbase Version compatibility

	HBase-0.92.x	HBase-0.94.x	HBase-0.95
Hadoop-0.20.205	S	X	X
Hadoop-0.22.x	S	X	X
Hadoop-1.0.0-1.0.2	S	S	X
Hadoop-1.0.3+	S	S	S
Hadoop-1.1.x	NT	S	S
Hadoop-0.23.x	X	S	NT
Hadoop-2.x	X	S	S
HBase requires hadoop 1.0.3 at a minimum; there is an issue where we cannot find KerberosUtil compiling against earlier versions of Hadoop.

Where

S = supported and tested,
X = not supported,
NT = it should run, but not tested enough.

Because HBase depends on Hadoop, it bundles an instance of the Hadoop jar under its lib directory. The bundled jar is ONLY for use in standalone mode. In distributed mode, it is critical that the version of Hadoop that is out on your cluster match what is under HBase. Replace the hadoop jar found in the HBase lib directory with the hadoop jar you are running on your cluster to avoid version mismatch issues. Make sure you replace the jar in HBase everywhere on your cluster. Hadoop version mismatch issues have various manifestations but often all looks like its hung up.