I was trying to work through External Table in SQL Server 2016 and was configuring the prerequisites , this is when i got stuck with error while creating EXTERNAL DATA SOURCE

CREATE EXTERNAL DATA SOURCE sql2016ds 
WITH
(
  TYPE = HADOOP,
  LOCATION = 'wasbs://containername@account.blob.core.windows.net/',
  CREDENTIAL  = cred_azstorage);
GO

Error

Msg 102, Level 15, State 1, Line 31
Incorrect syntax near 'CREDENTIAL'.

I searched a lot in msdn , but as the error is so ambiguous that it never strike my mind that it could be due to missing PolyBase Query Service

For those who have not heard or worked with PolyBase, it is not a totally new feature as it has existed on the PDW…err APS appliance for sometime now. So what is it? In short, PolyBase allows you to use your vast array of T-SQL skill to  query, join and manipulate unstructured or semi-structure data stored either in HDFS (HADOOP) or Azure Blob Storage directly from the SQL Server relational environment.

So, what i have to do to get over the error

You need to add [PolyBase Query Service for External Data] feature to your 2016 SQL Server Instance.Once feature is successfully installed recycle the sql server services.