Does Tableau integrate with Hadoop/ HiveServer?

Yes. Tableau connects to Hadoop through Hive, using the HiveServer2 connector with an appropriate ODBC driver — Cloudera, Hortonworks and MapR distributions are all supported, along with Amazon EMR.

The connection is to Hive rather than to Hadoop directly, because Hive provides the SQL-like interface Tableau needs. Impala and Spark SQL connectors exist as well and are usually faster for interactive work.

The practical consideration is latency. Hive queries can be slow enough that a live connection makes for an unpleasant dashboard, so extracting a summarised subset is the common approach — or better, aggregating in the cluster and pointing Tableau at the result.