Comment 5 for bug 1178333

There are two issues that causes this bug. Once is what i described previously , where the instance fails when creating sec-group. The quota rolls back but the instance does not. This is being addressed in BP security-groups-workflow-update.

Another issue that could cause this is when two requests from the same tenant gets to the API. During the quota reservation, the quota reserve counter gets set, instead of being incremented. This can cause the reservation of one of the request be overwritten