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Hi everyone,

I have a setup with 2 controllers and 2 compute nodes. For testing 
purposes, I want to make sure that when I send a request for launching a 
new instance, it's being processed by a particular scheduler. For this I 
have several options:

1) ssh to controller with scheduler I don't want to use and power it down

2) disable scheduler using nova api

Option #2 seems much cleaner and effective to me (less time needed to 
get service up and running again), but looks like I'm missing something 
very important in how nova disables service.

My `nova service-list` gives me the following:

+----+------------------+-------------------------------------+----------+----------+-------+----------------------------+--------------------+
| Id | Binary           | Host                                | Zone     
| Status   | State | Updated_at                 | Disabled Reason    |
+----+------------------+-------------------------------------+----------+----------+-------+----------------------------+--------------------+
| 25 | nova-consoleauth | controller1 | internal | enabled  | up    | 
2017-05-08T08:46:09.000000 | -                  |
| 28 | nova-consoleauth | controller2 | internal | disabled | up    | 
2017-05-08T08:46:10.000000 | -                  |
| 31 | nova-scheduler   | controller1 | internal | enabled  | up    | 
2017-05-08T08:46:14.000000 | -                  |
| 34 | nova-scheduler   | controller2 | internal | disabled | up    | 
2017-05-08T08:46:17.000000 | Test |
| 37 | nova-conductor   | controller1 | internal | enabled  | up    | 
2017-05-08T08:46:13.000000 | -                  |
| 46 | nova-conductor   | controller2 | internal | disabled | up    | 
2017-05-08T08:46:13.000000 | Test |
| 55 | nova-compute     | compute1 | nova     | enabled  | up    | 
2017-05-08T08:46:10.000000 | -                  |
| 58 | nova-compute     | compute2 | nova     | enabled  | up    | 
2017-05-08T08:46:16.000000 | -                  |
+----+------------------+-------------------------------------+----------+----------+-------+----------------------------+--------------------+

But when I run request for new instance (either from python-client, 
command line or horizon), I see in logs that nova-scheduler at 
controller2 is working to process that request half of the time. The 
same behavior as if I didn't disable it at all.

I've read some code and noticed that each nova-conductor is always 
paired up with the scheduler on the same controller node, so I've 
disabled nova-conductor as well on controller2. Which didn't change 
anything.

While I'm going through the code of nova-api, could you please help me 
to understand if it's a correct behavior or a bug?

Thanks in advance for your time.