Comment 2 for bug 1430616

I tried to stop ironic-api while nova-compute is running and I reproduced the same behavior as you pasted. For this bug, it only happened at the start up phase.
Personally I don't think it's a right behavior to just shutdown nova-compute if ironic-api service stopped. You can always launch an instance even if nova-compute is stopped. And you will get error like:
"message": "No valid host was found. There are not enough hosts available."
I also tried to just stop ironic-api but keeps nova-compute running, the same error for the instance:
"message": "No valid host was found. There are not enough hosts available."
So it's better to keep nova-compute and once ironic-api is back, it can recover immediately.

BTW, what information do you want to change the status back to normal from incomplete? Thanks.