Hello list! I've spent the better part of the afternoon upgrading from 0.19.3 to trunk, and I did fall into a hole or two. Specifically, it turns out that we rely on DNS lookups to find out what address HMaster binds to, which caused me some grief. The documentation is also weak on what part Zookeeper plays in the process; a stronger write-up of how HBase utilizes Zookeeper would be a great help in troubleshooting issues like this.
Basically, I saw the region servers trying to connect to 127.0.0.1:6000 without any hint as to why, neither in the (default) configuration nor the logs. HMaster happily reported this: INFO org.apache.hadoop.hbase.master.HMaster: My address is master2.internal.net:6000 quickly followed by: INFO org.apache.hadoop.hbase.master.HMaster: HMaster initialized on 127.0.0.1:6000 The cause was simple and my face-palm genuine as the realization struck me: there was a record for master2 in the hosts file, and it was pointing to 127.0.0.1. I suggest that an hbase.master.address option (that overrides any resolved address) would make it easier to get the installation up and running. Cheers, Fredrik
