Ansible, Pulumi etc allow you to script an infrastructure once the plan is in place. I'm looking at one step earlier; how to come up with an infrastructure plan automatically, given the requirements. Configurator is the wrong name, I realize now.
The plans generated by the system you describe would be very workload and requirement-dependent.
As you stated:
"Because each of these systems have different demands on cpu/memory/disk/network, they are inherently unequal in their effect. It is analogous to a recipe generator that spits out a recipe for a given number of people, where different components scale differently in terms of amounts and cooking time."
I do not think there is a good way to design such a system for a general use case, but it might be possible to build an expert system (https://en.wikipedia.org/wiki/Expert_system) for some specific use cases using well understood infrastructure patterns.
For example, you might have a recipe for a database-backed website that can handle given amounts of throughput and has best practice configurations for scaling, data backup, failover, etc.
It seems like a tough problem for the general case, but doable for "typical" business use cases.
All true. I guess I am looking for a first approximation, so that one can have a starting point from which one can fine-tune. The problem is to somewhat mimic what an expert might do given the requirements, to say, for example, "We'll have 5 48-core boxes, three of which will have Kafka, two will have the database, the in-memory grid will be spread over all 5 etc, and here are the relevant config files". Maybe it spits out ansible code.
