Summary
Writing your own Hadoop-YARN applications allows Hadoop users to apply their own business logic (other than MapReduce programming) in a distributed environment. This chapter covered the basics of the YARN APIs and walked you through how to write a simple YARN application. To read more about the topic, you can refer to the Hadoop documentation at http://hadoop.apache.org/docs/r2.5.1/hadoop-yarn/hadoop-yarn-site/WritingYarnApplications.html.
The Hadoop documentation covers a bird's eye view of the APIs used while writing YARN applications. You can also refer to a sample Hortonworks project on GitHub at https://github.com/apache/hadoop-common/tree/trunk/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-applications/hadoop-yarn-applications-distributedshell. You can build and execute it on a Hadoop-YARN cluster.
The next chapter covers YARN insights and the core services related to YARN components. It'll help the Java developers and open source contributors to understand the communication between...
