sync of node power state should do more than log a warning

[aeva black]

Right now, _sync_power_states merely logs a warning if node.power_state does not match the physical machine's measured power state. It should do more than this depending on the situation, while respecting Nova's use of Ironic, the operator's direct requests, and any physical actions taken by NOC staff.

[Robert Collins (lifeless)]

SO yes- I think the best way to describe it is:
 - Ironic is authoritative on the power state except when a node is in maintenance.
 - Nova can tell Ironic what the power state should be
 - so can admins directly. [yes, this would let Nova and Ironic disagree, just like happens with VMs - thats fine].
 - Admins that want to own power for a node can put it in maintenance, unregister it or shut Ironic down.

[Ellen Hui (ellen-hui)]

So, if I understand this correctly, _sync_power_states should raise complain more loudly (log an error or raise an exception?) when node.power_state does not match power_state. Currently, if the node is in maintenance, the sync just skips it.

I'm a bit fuzzy on the desired behavior here, though; if the node is not in maintenance, and the power states disagree, what exactly should happen? In what cases should the conductor allow one of the two states to change, and in what cases should it refuse? Are there cases in which it's okay to change the physical state but not the recorded state, or vice versa?

[aeva black (tenbrae)]

I believe this bug has been resolved through the addition of a force_power_state_during_sync flag, and the addition of maintenance mode.

If there is disagreemnt, please re-open it.