Ginger Grant notes that Power BI Report Server is now generally available:
The most glaring change from what was announced earlier, is Power BI Report Server can only connect to analysis services data sources, both tabular and multidimensional. If you want to connect to SQL Server, Oracle or Excel or all three, use the Power BI Web Service. Only going to the cloud version will users be able to create a data mashup or connect to anything but SQL Server.
Connecting to one data source is not what was promised when the Power BI Report Server was announced in May. Various Power BI Product members held a session at the Microsoft Data Summit where attendees were able to ask questions. I asked “When are we going to be able to use Power BI Report Server with data sources other than analysis services?” In a room full of people, I was assured that it was a top priority of the team to release the same data connectivity functionality for Power BI Report Server that currently exists for Power BI Services and the current plan was to release this functionality the next release.
This is the most glaring flaw with Power BI Report Server at the moment. Unfortunately, that probably makes it DOA for my purposes, at least until they introduce SQL Server relational as a valid data source.