Apache Tez is a generic data-processing pipeline engine envisioned as a low-level engine for higher abstractions such as Apache Hadoop Map-Reduce, Apache Pig, Apache Hive etc.
At it's heart, tez is very simple and has just two components:
The data-processing pipeline engine where-in one can plug-in input, processing and output implementations to perform arbitrary data-processing. Every 'task' in tez has the following:
A master for the data-processing application, where-by one can put together arbitrary data-processing 'tasks' described above into a task-DAG to process data as desired. The generic master is implemented as a Apache Hadoop YARN ApplicationMaster.