Code review comment for lp:~rconradharris/nova/server_progress

So this looks really good from an implementation perspective. Beyond that, I really don't like that this kind of functionality is part of the API spec, which is of course not your fault. The following is a diatribe against the idea, not the patch.

Though the progress is done in a way that mostly keeps all the moving parts decoupled (since it's just a guess based on the number of expected steps rather than disk progress, as you mention,) I'm really not a fan of the false sense of security it will provide end users. Questions like "Why is my Linux instance at 25% for a quarter of the time a Windows instance is?" will pop up shortly. Moving to a model of disk progress has all sorts of other scary implications, like trying to track the copy progress through the XS plugin that is currently running (yuck) and I don't even know how you'd do it for the other hypervisors. It also opens up all kinds of synchronization issues when you start including zones and trying to bubble that data up to the API in a reasonably timely manner.

Long story short, I think including progress counters is a very strong statement regarding the type of cloud you expect it to be, and in this case, I don't think synchronous features like progress are indicative of the sort of scale we expect Nova to achieve.

If the community decides they want this, you can consider the above an "approve." I don't want to block it just because I might have a different idea of the Way Things Should Be™