Open Stack

On 14/11/13 11:29, Renat Akhmerov wrote:
> As for EventScheduler proposal, I think it actually fits Mistral model
> very well. What described in EvenScheduler is basically the ability to
> configure webhooks to be called periodically or at a certain time. First
> of all, from the very beginning the concept of scheduling has been
> considered a very important capability of Mistral. And from Mistral
> perspective calling a webhook is just a workflow consisting of one task.
> In order to simplify consumption of the service we can implement API
> methods to work specifically with webhooks in a convenient way (without
> providing any workflow definitions using DSL etc.). I have already
> suggested before that we can provide API shortcuts for scheduling
> individual tasks rather than complex workflows so it has an adjacent
> meaning.
>
> I other words, I now tend to think it doesn’t make sense to have
> EventScheduler a standalone service.

I tend to agree. What OpenStack doesn't yet have is a language for 
defining actions (Heat explicitly avoids this). This is required to 
define what to do in both a workflow task and a scheduled task and we 
only want to define it once, so workflow-as-a-service and 
cron-as-a-service (yeah, I know, people hate it when I call it that) are 
closely related at that level. Given this, it seems easiest to make the 
latter a feature of the former. I can easily imagine that you'll want to 
include scheduled tasks in your workflows too.

What might be a downside is that sharing a back-end may not be 
technically convenient - one thing we have been reminded of in Heat is 
that a service with timed tasks has to be scaled out in a completely 
different way to a service that avoids them. This may or may not be an 
issue for Mistral, but it could be resolved by having different back-end 
services that communicate over RPC. The front-end API can remain shared 
though.

cheers,
Zane.

>
> What do you think?
>
> Renat
>
> On 13 Nov 2013, at 06:39, Angus Salkeld <asalkeld at redhat.com
> <mailto:asalkeld at redhat.com>> wrote:
>
>> On 12/11/13 15:13 -0800, Christopher Armstrong wrote:
>>> Given the recent discussion of scheduled autoscaling at the summit
>>> session
>>> on autoscaling, I looked into the state of scheduling-as-a-service in and
>>> around OpenStack. I found two relevant wiki pages:
>>>
>>> https://wiki.openstack.org/wiki/EventScheduler
>>>
>>> https://wiki.openstack.org/wiki/Mistral/Cloud_Cron_details
>>>
>>> The first one proposes and describes in some detail a new service and API
>>> strictly for scheduling the invocation of webhooks.
>>>
>>> The second one describes a part of Mistral (in less detail) to
>>> basically do
>>> the same, except executing taskflows directly.
>>>
>>> Here's the first question: should scalable cloud scheduling exist
>>> strictly
>>> as a feature of Mistral, or should it be a separate API that only does
>>> event scheduling? Mistral could potentially make use of the event
>>> scheduling API (or just rely on users using that API directly to get
>>> it to
>>> execute their task flows).
>>>
>>> Second question: if the proposed "EventScheduler" becomes a real project,
>>> which OpenStack Program should it live under?
>>>
>>> Third question: Is anyone actively working on this stuff? :)
>>
>> Your work mates;)https://github.com/rackerlabs/qonos
>>
>> how about merge qonos into mistral, or at lest put it into stackforge?
>>
>> -Angus
>>>
>>>
>>> --
>>> IRC: radix
>>> Christopher Armstrong
>>> Rackspace
>>
>>> _______________________________________________
>>> OpenStack-dev mailing list
>>> OpenStack-dev at lists.openstack.org
>>> <mailto:OpenStack-dev at lists.openstack.org>
>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>
>>
>> _______________________________________________
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
>> <mailto:OpenStack-dev at lists.openstack.org>
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>
>
>
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>