Assessing and Securing a Domainless Architecture

Hi all, I've been doing a lot of research on how to assess for threats and risks in a Cloud Environment, Service Oriented Architecture, etc., but I'm not finding or correlating a lot of information on how assess or even harden a domainless environment. Okta, Jumpcloud, etc. (the primary vendors of the buzzword), have minimal information published that isn't dripping with verbiage that makes the solution seem like it solves all the world's security issues.

Does anyone have experience with …

architecture cybersecurity domainless