Building a REST Job Server for interactive Spark as a service
Livy is a new open source Spark REST Server for submitting and interacting with your Spark jobs from anywhere. Livy is conceptually based on the incredibly popular IPython/Jupyter, but implemented to better integrate into the Hadoop ecosystem with multi users. Spark can now be offered as a service to anyone in a simple way: Spark shells in Python or Scala can be ran by Livy in the cluster while the end user is manipulating them at his own convenience through a REST api. Regular non-interactive applications can also be submitted. The output of the jobs can be introspected and returned in a tabular format, which makes it visualizable in charts. Livy can point to a unique Spark cluster and create several contexts by users. With YARN impersonation, jobs will be executed with the actual permissions of the users submitting them. Livy also enables the development of Spark Notebook applications. Those are ideal for quickly doing interactive Spark visualizations and collaboration from a Web browser! This talk is technical and details the architecture and design decisions taken for developing this server, as well as its internals. It also describes the alternatives we tried and the challenges that were faced. The capabilities of Livy will then be lived demo in Hue’s Notebook Application through a real life scenario.