Multitenancy in Spring Cloud

after talking with a large financial services company that's building a SaaS offering, we discovered a few opportunities to better support multi-tenancy in a SaaS offering:

• how do we make Hystrix tenant aware? It would be nice, for example, if the @HystrixCommand took a SpEL expression for the key so that we could distinguish circuits based on request context. The company I spoke to ended up using an alternative circuit breaker implementation called JRugged because it was easy enough to plug this in, as I understand it.
• how do we handle service registration and discovery based on request context? Right now Eureka registration is per JVM. How do we qualify registration (and discovery) based on request context?
• how do we handle config server multi-tenancy, e.g.: given request context, load a different set of configuration files.

The issue identifies @HystrixCommand, Eureka registration and discovery, and config server behavior as separate areas for investigation. Start by reviewing those entry points and the existing request context handling; the issue does not name files or tests or define a bounded completion criterion, so the scope and acceptance criteria need clarification first.