Comment 1 for bug 1729621

I see solutions:

1. Change self._init_compute_node() in _update_available_resource() to not call self._update(), maybe by introducing new boolean parameter in _init_compute_node() args to not call self._update().

2. Add some kind of db transaction (Its not a good idea I think)

3. Modify calls of self._host.list_guests() to list all instances (those shutdowned too) - but for sure it will break other things

4. Re-organize code (?)