As promised, MapReduce support is once again working! Neptune 0.0.8 fixes this support, so when you use an input job to put your data into the underlying datastore, it will also put it into HDFS in case you want to use it for MapReduce later. The test suite includes test cases for regular Hadoop MapReduce via Java WordCount, and for Hadoop MapReduce Streaming via a Ruby implementation of the Embarassingly Parallel NAS Benchmark.
Also, I forgot to mention back in the 0.0.7 release that Walrus support was fixed, so just like for Google Storage, you can run the following:
neptune( :type => output, :storage => "walrus", :EC2_ACCESS_KEY => "your access key", :EC2_SECRET_KEY => "your secret key", :S3_URL => "http://ip of storage box/services/Walrus" )
We also changed it so that for all the S3-like storage backends, you need to specify the URL starting with http, so keep that in mind when deploying jobs.
Also, the test coverage is up to almost 87%, as we now cover many more failure conditions:
So update your Neptune gem and get coding!