I'm not saying to use AD for a SaaS product, I'm saying the advice on having an obscure domain is a bad one. The SaaS product is saas.com, the company domain is company.com, and the IPA or AD Domain is domain.company.com. I don't see any good reason to have a 3rd domain floating around for directory services. If anything it is another thing to manage and keep track of.
So what should be used for SaaS directory infrastructure?
Re:Security 101 for SaaS startups
by inopinatus on Tuesday March 07, 2017 @09:53PM
(#13817481)
That's a damn fine question. There's probably a book in it.
Briefly, though, keep it federated; layering integrity is super important for systematic consistency and quality, so wherever possible, entities should register using the tools provided by the PaaS/IaaS layers that the SaaS is inevitably running on. This includes any home-grown PaaS/IaaS, which are pretty common in SaaS at scale. I like to delegate a DNS subdomain to each subsystem, which is then served either natively from that subsystem (e.g. because its control plane used etcd) or using script-generated zones served by nsd. The only central aspect I want is the meta-directory that contains, ideally, nothing but delegations under the infrastructure domain name.
Also, no-one should be using AD for SaaS infrastructure. It is a pretty good product for your enterprise internal services, but cannot handle the rather different needs of a SaaS system directory.