Funny, we just had this just hit the front page against environment variables for secrets. https://news.ycombinator.com/item?id=8826024

It's not clear from the doc you linked that you would support AWS STS, which is probably the right way to approach minimal privilege and to reduce the time window that an attacker would have the privileges of the entity compromised. Wish I had a way to calculate that out from the tools I had which helps drastically during an investigation to sift through network logs.

What you seem to have built so far is what could be used to build a more modern shared secret access stack rather than being a full solution itself. Most companies that want to pay for something want to have something that will rotate out keys & passwords or enforce secrets policies like separation of keys across different nodes in your high availability solution for them (eg. the DB, root, and LDAP cached passwords should not be stored on the same data node even in encrypted form). Otherwise, a lot of companies have built equivalent solutions like Conjur already (to varying degrees of success depending upon how dysfunctional their IT already is). A lot of the custom solutions I'm familiar with in Defense / IC space are starting to use Apache Accumulo to enforce a great deal of sharing and storing of secrets. The architecture of that makes it possible to have tables split both column-wise and row-wise across multiple nodes based upon business rules like HIPAA, FISMA, PCI-DSS, etc. Tack on Zookeeper with some SASL and you'll spend the next year or two just arranging the meetings to figure out the security rules.

For an analogy, it seems like you've built a lot of the workings of Postgres missing something important like procedural queries and triggers, but organizations really want an ORM (they just don't even realize it because the whole industry is built around bikeshedding topics in security). Build something respecting the vernacular and culture of engineers, IT opsec / compliance, and (more importantly) the managers of both orgs and you should have a winner. Ok, after you find the right sales guys to get the attention of some F500s that are in terrible industries wracked by compliance BS 24/7.

All in all, good idea and it looks promising, I'll keep your product in mind if I can get a management tool like this even suggested. We're doing some extremely bad practices at present in order to avoid violating OTHER no-nos keeping stuff out of the public cloud, and our IAM across dozens and dozens of AWS accounts is completely bonkers and the bungling of the credentials as the after-effect is probably causing worse security problems than if we just gave them all the same keypairs. It'd be really interesting to see this work seamlessly across both AWS-like environments and a vSphere/vCAC/vCD type of environment using affinity / anti-affinity rules to make initial guesses about your security configuration. Pretty sure everything in an autoscaling group should be by default in the same group or "layer" (in your terminology), for example, and you could start with the same for vSphere compute clusters, unless host anti-affinity rules for a VM are present, which usually means that the VM is not allowed to cross a physical boundary and is a hint at a business level policy rather than a technical one (nobody does cross-geographic clusters besides Google last I saw, and you probably aren't going to be able to sell this to them....).

One thing that would tremendously help in your documentation would be to provide security scenarios for different user stories and potential users. Admins across multiple tenant business units have different use cases than developers that are working in maybe one or two organizations / groups, for example. I found myself expecting a "I am a... X, Y, Z" set of tabs and wanted to see each of their use case scenarios for one or two sample companies with different needs. Besides the "I don't want to be your guinea pig" mentality, this is what companies are really looking for half the time they ask for a reference customer.