I don't think there's anything special to know, beyond what's documented in the RHadoop subprojects. So it's not something that we ship, support or document separately. I have set up the rhadoop libraries with CDH and it's straightforward.   It's really a set of client side libraries that you install into *R*, not *Hadoop*. However to run rmr2 you will need R installed locally on all of your Hadoop cluster nodes, since it will run MapReduce jobs that execute R scripts.   I recall that you have to install a bunch of other R packages before installing the rhdfs/rhbase/plyrmr libraries, and I found this in my notes as the set of prerequisites:     install.packages(c("Rcpp", "RJSONIO", "bitops", "digest", "functional", "reshape2", "stringr", "plyr", "caTools", "rJava", "dplyr", "R.methodsS3", "Hmisc")) ... View more

You can also just add the HIve jars to your app classpath. The catch here is that Spark doesn't quite support the later version of Hive in CDH. This might work for what you're trying to do, but if you build your own, you're building for a slightly different version of Hive than you run here. ... View more

In bash for example: unset VARIABLE   ... View more

It's just an env variable; you can always "export VARIABLE=VALUE" in the shell. But this message is not an error. In fact you want to see this if you intend to run on a cluster. ... View more

Mahout is already shipped with CDH. It's not something you really install; it's a library. Can you say any more about the problem you are facing? ... View more

What is null? I don't see you using a broadcast fariable in a closure here. You just put one in a static member, which isn't going to work. ... View more