Hello, After upgrading from 0.6 to 0.7, we have experienced a strange error with MapReduce jobs. Jobs that ran perfectly before now seem to have trouble finding the classes from our code. The stack trace is long, but the errors happen in MapTask.run() when it tries to get the map output key class from the JobConf, which is probably the first time any of our classes are loaded. Then it fails with a ClassNotFoundException.
The strange thing is, the error does not occur on all of the machines in the cluster. As far as we can tell, the Hadoop installation and configuration are the same across the machines. Downgrading to 0.6 fixes the problem. Has anyone experienced something similar, or have any idea what could be causing this problem? Something incorrectly configured, maybe? Thanks, Albert
