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On 04/05/2015 11:21 PM, Chris Friesen wrote:
> On 04/05/2015 09:17 PM, Jay Pipes wrote:
>> On 03/30/2015 03:16 AM, Balázs Gibizer wrote:
>>> Hi,
>>>
>>> I have the following scenario. I have an application consisting of
>>> multiple VMs on different compute hosts. The admin puts one of the
>>> hosts into maintenance mode (nova-manage service disable ...) because
>>> there will  be some maintenance activity on that host in the near
>>> future. Is there a way to  get a notification from Nova when a host
>>> is put into maintenance mode? If it is not the case today would the
>>> nova community support such an addition to Nova?
>>>
>>> As a subsequent question is there a way for an external system to
>>> listen to such a notification published on the message bus?
>>
>> Hi Gibi!
>>
>> I don't believe there is a notification currently sent when a service is
>> disabled. I agree this would be a good (and pretty easy) addition to
>> Nova.
>>
>> Please feel free to add a blueprint in Launchpad. I don't see this as
>> needing a
>> full spec, really. It shouldn't be more than a few lines of code to
>> send a new
>> notification message.
>
> Wouldn't a new notification message count as an API change?  Or are we
> saying that it's such a small API change that any discussion can happen
> in the blueprint?
>
> (I'm trying to figure out how this relates to
> "http://docs.openstack.org/developer/nova/devref/kilo.blueprints.html"
> which says that any API change requires a spec.)

Hmm, good point. I think this is kinda borderline whether it's an API 
change, but probably best to be safe and submit a small spec. Thanks, Chris.

> Also, if the notification messages are considered part of the API,
> should they be versioned?

Personally, I believe they should, and I've said that on this mailing 
list before :)

http://lists.openstack.org/pipermail/openstack-dev/2015-January/054716.html

Best,
-jay