I don't think it supports AAD, just AD. You got me way too exited for a minute.
Some way of signing into Ubuntu with a custom SAML provider would be very cool. Windows supports it via their "credential provider"[0] framework and Google uses that to provide sign-in for Windows with your GSuite credentials.
[0]: https://docs.microsoft.com/en-us/windows/win32/secauthn/cred...
A bit frustrating, as you can otherwise join a windows 10 desktop (or vm) to just azure ad for sso etc.
[1] https://docs.microsoft.com/en-us/azure/active-directory-doma...
well that depends, the higher subscriptions include it for free.
sadly not for desktops, btw. you can create your own pam provider (grant_type=password) and put it into sssd (for local cache), but that does not work with 2fa.