if local hostname doesn't resolve, HttpServer2 fails with a kerberos exception

When a service (NN, DN) is started and the local hostname isn't in /etc/hosts, things will, obviously, fail.

However, the failure is reported as a wrapped Kerberos Exception, rather than going via the NetUtils.wrapException handling code java.lang.RuntimeException: Could not resolve Kerberos principal name: java.net.UnknownHostException: xubunty: xubunty: unknown error

The text is a dangerous distraction from the real cause. Especially as it appears even on systems which aren't running kerberos.

A fail-fast check could go into the http server startup process ahead of the security setup; NetUtils could add special reporting of the unknown-local-host problem