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Excerpts from Joshua Harlow's message of 2013-09-11 09:11:06 -0700:
> Sure,
> 
> I was thinking that since heat would do autoscaling persay, then heat would say ask trove to make more databases (autoscale policy here) then this would cause trove to actually callback into heat to make more instances.
> 
> Just feels a little weird, idk.
> 
> Why didn't heat just make those instances "on behalf of trove" to begin with and then tell trove "make these instances into databases". Then trove doesn't really need to worry about calling into heat to do the instance creation "work", and trove can just worry about converting those "blank instances " into databases (for example).
> 
> But maybe I am missing other context also :)
> 

That sort of optimization would violate encapsulation and make the system
more complex.

Heat doing Trove's provisioning and coordinating Trove's interaction with
other pieces of the system is an implementation detail, safely hidden
behind Trove. Interaction between other pieces of the end user's stack
and Trove is limited to what Trove wants to expose.