[openstack-dev] [ceilometer] time based auto scaling

Fei Long Wang feilong at catalyst.net.nz
Wed Apr 29 04:49:22 UTC 2015

+1, if you really care about time range, Mistral can meet your requirements.

Besides, maybe not directly related, as for autoscaling, I always
believe there should be a message queue service(like Zaqar) between the
(web) application and the worker, a task request will be posted to the
queue as a message, worker will pick the message from the queue to
handle. And then we can trigger the autoscaling based on the workload of
queue instead of the hardware usage. Just drop my 2 cents.

On 29/04/15 16:39, Fox, Kevin M wrote:
> what about Mistral?
> https://wiki.openstack.org/wiki/Mistral
> Thanks,
> Kevin *
> *
> ------------------------------------------------------------------------
> *From:* ZhiQiang Fan
> *Sent:* Tuesday, April 28, 2015 9:23:20 PM
> *To:* OpenStack Development Mailing List
> *Subject:* [openstack-dev] [ceilometer] time based auto scaling
> Hi devs,
> I'm thinking to add new type of alarm for time based auto scaling, but
> not sure if there is a better way to achieve it outside ceilometer scope
> Currently we can auto scaling based on vm load, but it will take
> several minutes to do it. For the worst case, when the vm load is
> heavy, ceilometer needs 10 minutes (by default) to collect the
> performance data, and alarm need 1 minutes to evaluate it, maybe there
> is evaluation_periods which set to higher that 1 to avoid performance
> peak. 
> So even though we can collect data by 1 minutes, but evaluation
> periods may be set to 3, so the worst case is after vm load perfomance
> in high level for 4 minutes, then the alarm is triggered, then heat
> will expand vm count, nova will take dozens seconds or more to create,
> finally the service on the in the heat server group will performance
> bad or unavailable for several minutes, which is not acceptable for
> some critical applications.
> But if we can know some high load which related with time, for
> example, 08:00am will be a peak, and after 22:00pm will definitely
> drop to idel level, then heat can increase some vms at 07:30am, then
> decrease some vms at 22:00 (or decrease by load as normal routine)
> However, current ceilometer only provide time constraint alarm, which
> will only evaluate but not guarantee it will be triggered. And heat
> cannot provide something like timer, but just can wait for the signal.
> So I propose to add a new type of alarm, which will definitely send a
> signal to action when it is evaluated (with or without repeat, it will
> work well with time constraint)
> Any suggestion?
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Cheers & Best regards,
Fei Long Wang (王飞龙)
Senior Cloud Software Engineer
Tel: +64-48032246
Email: flwang at catalyst.net.nz
Catalyst IT Limited
Level 6, Catalyst House, 150 Willis Street, Wellington

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