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In Pictures: 18 essential Hadoop tools for crunchi...
Breaking up a job into steps simplifies everything. If you break your project into multiple Hadoop jobs, Oozie is ready to start them up in the right sequence. You won't need to babysit the stack, waiting for one job to end before starting another. Oozie manages a workflow specified as a DAG (directed acyclic graph). (Cyclic graphs are endless loops, and they're traps for computers.) Just hand Oozie the DAG and go out to lunch.
The image at left shows one flowchart from the Oozie documentation. The code, protected by the Apache license, is found at http://oozie.apache.org/.
In Pictures: 18 essential Hadoop tools for crunching big data