Forum Discussion
Azure Active Directory and ADFS
No, you cant, as Azure AD is NOT any sort of replacement for "traditional" AD. You cannot "join" servers to it. You can however spin up Azure VM in the cloud and extend your on-premises AD with a DC running in Azure, and deploy AD FS as well. Take a look at the guidance here to get started: https://msdn.microsoft.com/library/azure/jj156090.aspx
There is no automatic fallback option, neither with AD FS or PTA. First of all, you should be deploying them in HA configuration, at least 2 machines and preferably in different datacenters, at a minimum. Some people choose to have one of the AD FS farm nodes in Azure VM.
If all AD FS nodes are down, you have to perform manual actions to change the authentication method. Same goes for PTA. Having password sync configured as backup (https://social.technet.microsoft.com/wiki/contents/articles/17857.dirsync-how-to-switch-from-single-sign-on-to-password-sync.aspx#Temporarily_Switching_from_Single_Sign-On_to_Synchronizated_Passwords_for_Sign-In) is a way to make the process faster/easier, but it's not an automatic failover solution.
