https://aws.amazon.com/blogs/enterprise-strategy/6-strategies-for-migrating-applications-to-the-cloud/

 

https://www.theregister.co.uk/2019/01/24/office_365_down/

But not for consumers? SP and Mail and Azure are working on standard Domain, Hope there will be something to learn..

There is a fundamental question to this issues: the domain controllers are Windows/Azure or Linux based? Hypothetical it would be possible to be Linux and or Samba based on ms own extensions, because the Azure Service supports only a subset of an on premises AD.