[placement][nova][ptg] Resourceless trait filters

Jay Pipes jaypipes at gmail.com
Mon Apr 22 19:23:20 UTC 2019

On 04/10/2019 12:51 PM, Ed Leafe wrote:
> On Apr 9, 2019, at 12:22 PM, Chris Dent <cdent+os at anticdent.org> wrote:
>>         * (My brain hurts from the concept for a provider that
>>           provides nothing. Perhaps it provides something we aren't
>>           remembering to count?)
> This was a big bone of contention back when Traits were first being discussed: they can only be applied to RPs. So if you had a single physical PCI device that provided virtual functions, and some of those VFs were, say, private net and the others were public, you had to create intermediary RPs between the PCI RP and the VFs so that you could tag those RPs with the correct trait to distinguish them.
> That brain hurt is very much why I argued against this restriction back then. But it's what we ended up with, so those "virtual" RPs are with us for good. If it helps, think of them as not providing resources, but providing other resource providers.
> Does that hurt a little less?

Note that if we used a single "apply aggregate association and trait 
constraints in a self-and-children manner" policy, everything would be 
much easier to reason and think about.


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