Although the main goal of this chapter was to focus on data processing in Hadoop using the R language, throughout its various parts and sections you've been exposed to numerous different techniques and approaches used in Big Data analytics. We only hope that it wasn't too overwhelming!
We kicked off by introducing you to the diversity of Hadoop ecosystem, its tools and applications available to users, HDFS, and MapReduce frameworks.
We then created a single-node Hadoop cluster in which we carried out a simple word count MapReduce exercise in Java and the R languages, and we also showed you how to manage HDFS from the Linux command line and RStudio Server.
Finally, we achieved something that you probably won't be able to find in many (if any!) R books currently available on the market. We setup and configured a fully operational multi-node Hadoop cluster with R and RStudio Server installed and we crunched some real Big Data around 414,000,000 rows of electricity smart meter readings...