Comment 2 for bug 1545675

As someone with familiarity with the shelve/unshelve process that analysis makes sense to me. Updating resource usage on offload is something that should be done since resources are not in use, or "reserved", at that point. Clearing the host on a failed claim makes sense as well since as was pointed out there is nothing on the host at that point and therefore no real association with that host.

Something else to note is that shelving code leverages much of what resize did at the time it was written, so any issues discovered in that path may also affect resize. Though Tempest tests may not be resizing instances so shelving tests tend to find issues first.