Comment 10 for bug 1469179

Tobias: As you've seen just setting the disk values to 0 in the request spec isn't enough because that is only really used by the scheduler, which doesn't currently do resource tracking. I think it needs to be made clear that root_gb, and really all of the disk sizes, only apply to local disks. So the right thing to do would be to set it to 0 when booting from a volume. The patch from Feodor looks like the right approach for that.

The other side of it is what's shown in the API, and therefore what Horizon displays. Some consideration should be given to whether the disk size exposed should be the local disk or the root disk. My first hunch says that we should display root_gb as 0 and require the disk size to be extracted from the volume info. If we displayed root_gb == volume_size that could lead to confusion as to why the root_gb is > the max disk size allowed by a flavor.