I am trying to make my way through a lot of Azure documentation on multitenant identity management, for a bespoke ASP.NET MVC SaaS site. It is difficult as it seems that a lot of the online examples and articles are now outdated and not applicable to latest VS templates, and other vague aspects, such as determining what is Preview and what is not. Also, MS tend to use the word "multitenant" when specifically dealing with partner companies who have their own Azure AD, which is not our case.
Our proposed system will offer a web application to different customers. The backend will have a separate db per customer (tenant). The front end will select which db connection (and probably use impersonation) depending on the logged in user. The identity management would preferably be offloaded to Azure ACS, so that in future if we want to integrate with corporations with their own Federation identity provider we can, but for those smaller companies that don't have their own domain, we want to create accounts on their behalf.
I am thinking that a good way to do this is by using Azure ACS (for federating with corporate customers) and a general Azure AD directory (for everyone else), where in the second case I create a group per tenant (customer). Then, in Azure ACS, I translate all claims, either the group from my own AD, or the company name from the federated identity provider, and use that in the MVC app to establish the tenant.
Is this an OK way to do it? Am I overlooking some standard, simple way that Azure already offers? Is this future proof wrt to the Azure roadmap?
for the latest multi tenant samples please see https://github.com/Azure-samples?utf8=%E2%9C%93&query=multiten. We are about to release more documentation on how to handle multi tenancy in Azure AD. I would strongly advise against using ACS in any new project, given that we are no longer adding any features and we are actively working on migrating functionality from ACS to Azure AD. See http://blogs.technet.com/b/ad/archive/2015/02/12/the-future-of-azure-acs-is-azure-active-directory.aspx for more details.