See issue #6 - the Hadoop integration relies on the dependencies form Hadoop instead of ElasticSearch - the reason? when you deploy against Hadoop, you have a small, stand-alone jar that you can use.

Seems ideal, but that's only going to work with particular versions/builds of Hadoop it seems. Perhaps we ought to have a branch that simply includes the current elasticsearch version; which provides for both client modes (joining a node and remote http posts) and json serialization. It does seem like the object mapper should not be an absolute requirement in the API, given that the object may already be a valid json string.

Currently it's going to work with the entire 1.x version which is the only one marked as stable. For Hadoop 2.x will revise it but so far it looks okay since the existing code works with the updated libraries.
Not sure why you mention elasticsearch - there's no code dependency on it (see the comment above). As for the object mapper, that's an internal implementation that might go away.
Not sure what you're referring to as an API but the Hive/Pig/InputOutput format do not expose that.

I had to do a few tweaks for Hadoop 0.20x. It's working, there were some tweaks, for whatever reason shutdown wasn't working.

I'd be interested in knowing what the tweaks were. Any reason why you're using Hadoop 0.20.x and not 1.x?

Currently elasticsearch-hadoop uses httpclient 3.1 while hadoop 1.x depends on 3.0.1 (https://svn.apache.org/repos/asf/hadoop/common/tags/release-1.0.4/ivy/libraries.properties).
This leads to NoSuchMethod exceptions as the 'shutdown()' method is only available in 3.1.
Hadoop 2.x though uses httpclient 3.1

@tzolov thanks for the heads-up. httpclient 3.1 is used since Hadoop 1.0.4 transitive dependencies rely on httpclient 3.1 while Hadoop only requires 3.0.1. I'm not sure why ivy doesn't catch that or at least why 3.1 doesn't actually shows up in the Hadoop distro, nevertheless I've fixed the build file to force the use of 3.0.1 and fixed the use of shutdown method.
Long term depending on performance testing, MultiThreadedHttpConnectionManager might be used instead of SimpleHttpConnectionManager and that has a proper shutdown method.