Open Stack

On Tue, Oct 25, 2016 at 12:12 AM, Zane Bitter <zbitter at redhat.com> wrote:
> On 22/10/16 10:38, Thomas Herve wrote:
>>
>> Hi all,
>>
>> One of my long time goal since I started contributing to OpenStack is
>> to try to remove polling where I can. With Zaqar WebSocket support, we
>> now have a transport available for users to connect to, and where we
>> can push notifications. We already leveraged that in Heat [1], so that
>> you can manipulate a stack and you'll be notified when its status
>> changes.
>>
>> Still, not everyone uses Heat, and under the hood it still polls for
>> you. We should be able to use the various notifications that projects
>> publish to push similar events. Ceilometer already consumes those
>> notifications and try to make them somewhat consumable [2].
>>
>> The missing piece is something that bridges Ceilometer and Zaqar. I
>> wrote a small service [3] which provide a simple API, so that you can
>> say "Subscribe to those events and send them to this queue". The data
>> flow looks like this:
>>
>> Service (Nova, Neutron) -> Notification -> Ceilometer -> Bridge ->
>> Zaqar -> User.
>>
>> This way, you'll get a Zaqar message per event, with some filtering
>> done by the bridge service. It's far from being ideal, as the
>> notification format is a endless topic of conversation, but I hope
>> that if we start using it things will move further. I also hope I can
>> get some feedback on the approach.
>
>
> Could you document what makes this different from
> http://docs.openstack.org/developer/aodh/event-alarm.html? (I can think of
> some ways, but it's not clear to me whether a separate service is the right
> thing or if the existing Aodh event alarms can be modified to do what we
> want.)

Asking the tough questions :). I don't know about the details, but
it's possible that since https://review.openstack.org/#/c/335289/ got
merged, you have the same possibilities nowadays. I'd need to test it,
in which case my service is not necessary anymore (though the other
questions still apply). But in terms of semantics, it feels a bit
weird to use alarming for continuous event retrieval.

-- 
Thomas