public class KerberosExtension
extends water.AbstractH2OExtension
Authenticates the H2O Node to access secured Hadoop cluster in a standalone mode.
This extension assumes that if Hadoop configuration is present and it has Kerberos enabled
the user will likely want to read data from HDFS even though H2O is running in a standalone mode (not on Hadoop).
The extension attempts to authenticate the user using an existing Kerberos ticket. This means the Kerberos ticket
needs to be manually acquired by the user on each node before the H2O instance is started.
The extension fails gracefully if the user cannot be authenticated and doesn't stop H2O start-up. The failure
will be logged as an error.