I would like to grant external business partner users access to my Power BI tenant using the Power BI Service so they have access to our reports just like my employees. I need to secure access using their User ID and RLS (likely using SQL Server 2016 RLS). I have a hundred or so reports to share with thousands of extneral business partners. I don't want to add them to my Office 365 tenant since they already have their own O365 tenant and most of them already have a license in their tenant to Power BI Pro, so I we don't want to purchase the same software twice. All these users already authenticate using SSO to more than dozen applications that we provide, so I would like to use the same credentials they already use. I've done a lot of reading on this site and have yet to find an approach that would meet our needs.
I have a few ideas:
1) If I could do forms based authentication to the Power BI Service and if Microsoft could verify that their external email address is already licensed for Power BI Pro, then I would be good.
2) If I could grant guess/external access to my Power BI Service tenant by providing an external AAD email addresses that would link to their O365 Power BI Pro license, then I would be good.
Any thoughts? I can't imagine I'm the only business that wants to provide external business partners access to their Power BI tenant.
Power BI doesn't provide sufficient features with us to make the external users get the same experience like the internal sharing currently. Regarding your two ideas:
#2. As Power BI tenant is fixed after signed up. If you use the Office 365 account sign up the Power BI, you might need to add them to this tenant. Otherwise, I'm afraid it's not possible.