What is oozie in Hadoop ?

Oozie is a workflow scheduler for Hadoop developed by Apache which runs the workflow of dependent jobs. In Oozie, users are permitted to create DAG's (Directed Acyclic Graphs) of workflows, which can be run in parallel and sequentially in Hadoop.

Oozie consists of two parts; workflow engine and coordinator engine. It is scalable and can handle the timely execution of thousands of workflows (each consists of dozens of jobs) in a Hadoop cluster. Moreover, Oozie is very much adjustable, as well. One can easily start, quit, suspend and rerun works. It makes it very easy to rerun broken workflows.