Comment 2 for bug 1012822

1st scenario : During the scheduler activities during instance create, the scheduler updates its compute node level data before the request to spawn even reaches the compute node. So if the instance is in ERROR state during these activities, i think we can ignore updating the resource consumed by that instance in the host manager update call.

2nd scenario (wangpan has pointed out) : Instance is being spawned by hypervisor and disk has been created and something goes wrong and instance goes into ERROR state, This case should be handled by the periodic resource tracker and not the host_manager since host manager has no idea about whats happened at hypervisor.

do these approaches sound alright?