although i don't know the nova internals that well, i will respond with my sig api hat on. On Tue, Feb 12, 2019 at 1:28 PM Matthew Booth <mbooth@redhat.com> wrote:
I don't think it means n-api is at fault, I think it means that nova, as a whole, is temporarily unable to fulfil the request for reasons which can't be resolved using the API, but might be fixed if you wait a bit. The weird thing about this specific request is that, being an admin api, the person you might be waiting on to fix it might be yourself. It's still OOB, though: compute host down isn't something you can fix using the API. 409 to me means you raced with something, or something is in the wrong state, and you need to go do other things with the API before coming back here and trying again. 503 to me means we can't do it no matter what you do because, well, 'Service Unavailable'. Which it is, because the compute host is down.
i tend to concur with this reading as well. for me, when thinking about status codes in general i like to keep this in miind: 4xx means something has gone wrong but the client might be able to fix it by changing the request (this could mean many things), 5xx means that something has gone wrong on the server-side and continued requests will not "fix it". so, under the given example, i would expect a 5xx status code if the server is unable to respond to my request /regardless/ of how i format it or what uri i am accessing. just 2 more c to the pile =) peace o/