Just pushed a new implementation of discovery called "zen". Its an
implementation from the ground up for a high performance and optimize for
elasticsearch discovery module. It allows for two main additional features,
the first is the fact that a node can be configured to be a pure client
(i.e. not turn into a master, ever), and much better support for cloud
environments (once I implement it) - more on that soon.
The issue is: http://github.com/elasticsearch/elasticsearch/issues/issue/150
Note, this is now the default discovery, and the jgroups discovery moved to
be a plugin.