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On Mon, Aug 15, 2016, at 10:33 AM, Jay Pipes wrote:
> On 08/15/2016 09:27 AM, Andrew Laski wrote:
> > Currently in Nova we're discussion adding a "capabilities" API to expose
> > to users what actions they're allowed to take, and having compute hosts
> > expose "capabilities" for use by the scheduler. As much fun as it would
> > be to have the same term mean two very different things in Nova to
> > retain some semblance of sanity let's rename one or both of these
> > concepts.
> >
> > An API "capability" is going to be an action, or URL, that a user is
> > allowed to use. So "boot an instance" or "resize this instance" are
> > capabilities from the API point of view. Whether or not a user has this
> > capability will be determined by looking at policy rules in place and
> > the capabilities of the host the instance is on. For instance an
> > upcoming volume multiattach feature may or may not be allowed for an
> > instance depending on host support and the version of nova-compute code
> > running on that host.
> >
> > A host "capability" is a description of the hardware or software on the
> > host that determines whether or not that host can fulfill the needs of
> > an instance looking for a home. So SSD or x86 could be host
> > capabilities.
> > https://github.com/jaypipes/os-capabilities/blob/master/os_capabilities/const.py
> > has a list of some examples.
> >
> > Some possible replacement terms that have been thrown out in discussions
> > are features, policies(already used), grants, faculties. But none of
> > those seemed to clearly fit one concept or the other, except policies.
> >
> > Any thoughts on this hard problem?
> 
> I know, naming is damn hard, right? :)
> 
> After some thought, I think I've changed my mind on referring to the 
> adjectives as "capabilities" and actually think that the term 
> "capabilities" is better left for the policy-like things.
> 
> My vote is the following:
> 
> GET /capabilities <-- returns a set of *actions* or *abilities* that the 
> user is capable of performing
> 
> GET /traits <-- returns a set of *adjectives* or *attributes* that may 
> describe a provider of some resource

Traits sounds good to me.

> 
> I can rename os-capabilities to os-traits, which would make Sean Mooney 
> happy I think and also clear up the terminology mismatch.
> 
> Thoughts?
> -jay
> 
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