On the twitter hashtag #sqlhelp I saw a really dangerous (dangerous because it could cost your company a lot (somewhere between tens of thousands to hundreds of thousands of pick your favorite currency) bit of advice, that someone has received from their software reseller.
I’ll paraphrase the tweet so as to protect the guilty: “our reselller said that if we bought a license of enterprise edition, we could run the database engine on one server, and SQL Server Reporting Services on another.” This is 100% wrong, and always has been. Per the SQL Server 2019 licensing guide.
Even though SQL Server Reporting Services is separate installation now, the licensing is exactly the same as SQL Server. I think some of the confusion in the Twitter stream is related to the one of the terms of Power BI Reporting Service. If you purchase Power BI Reporting Services through your SQL Server licensing, it is treated exactly like any other SQL Server component for the purposes of licensing. That means, if you need a SQL Server database engine for your report server databases (the database that contains the PBI-RS metadata), you have two choices:
1) Install the database engine side by side with your PBI services
2) Buy additional cores to run the database engine on a different server.
This last bit is where it gets a little confusing. If you buy your PBI RS licenses through having Premium capacity in the Power BI service, you can install SQL Server standard edition, exclusively for the purposes of Power BI or other products like SSRS or SSIS that require a SQL Server database.
Customer may run any number of Instances of any SQL Server database software (SQL Server Standard) included in Power BI Report Server in one OSE on a Server dedicated to Customer’s use for the limited purpose of supporting Power BI Report Server and any other product that includes SQL Server database software. Dedicated Servers used for this purpose, that are under the management or control of an entity other than Customer or one of its Affiliates, are subject to the Outsourcing Software Management clause
That’s from the volume licensing guide.
tl;dr Always assume you need a license for production, unless you are paying for PBI premium and then you may have an engine license you can use just for that.