Comment 3 for bug 1581037

1) 9.0 As I pointed in milestone
2) I'm simply boot a VM with port and then trying to detach this port during booting. Nova responds with ERROR (Conflict): Cannot 'detach_interface' instance 094283e8-3ea5-4b69-8666-1bcd872a9101 while it is in vm_state building (HTTP 409) . I don't know is this really conflict or anything else, but explanation seems correct to me.
After such pooling of nova instance to detach port, nova successfully detaches port in some time.
After that, if you try to attach this port again, you'll receive Conflict and port will be deleted.
The problem here is that nova deletes port, but obviously shouldn't.