Is it possible to have a SQL Server cluster with Hadoop?
You cannot run SQL Server under Hadoop but you can query Hadoop data via T-SQL in SQL Server 2016.
This next edition of SQL Server includes a technology called PolyBase which allows access of Hadoop data and Azure blob storage from T-SQL. Tutorials are available from Microsoft at the bottom of the linked page.

SSIS for SQL Server 2016 has Hadoop connection managers available also: Hadoop File System Task.