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+1, if you really care about time range, Mistral can meet your
requirements.<br>
<br>
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.<br>
<br>
<div class="moz-cite-prefix">On 29/04/15 16:39, Fox, Kevin M wrote:<br>
</div>
<blockquote
cite="mid:1A3C52DFCD06494D8528644858247BF01A1F320A@EX10MBOX03.pnnl.gov"
type="cite">
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what about Mistral?<br>
<br>
<a class="moz-txt-link-freetext" href="https://wiki.openstack.org/wiki/Mistral">https://wiki.openstack.org/wiki/Mistral</a><br>
<br>
Thanks,<br>
Kevin <strong>
<div><font color="#000000" face="Tahoma" size="2"> </font></div>
</strong>
<hr tabindex="-1">
<font face="Tahoma" size="2"><b>From:</b> ZhiQiang Fan<br>
<b>Sent:</b> Tuesday, April 28, 2015 9:23:20 PM<br>
<b>To:</b> OpenStack Development Mailing List<br>
<b>Subject:</b> [openstack-dev] [ceilometer] time based auto
scaling<br>
</font><br>
<div>
<div dir="ltr">Hi devs,
<div><br>
</div>
<div>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</div>
<div><br>
</div>
<div>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. </div>
<div><br>
</div>
<div>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.</div>
<div><br>
</div>
<div>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)</div>
<div><br>
</div>
<div>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.<br>
</div>
<div><br>
</div>
<div>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)</div>
<div><br>
</div>
<div>Any suggestion?</div>
</div>
</div>
<br>
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<br>
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<pre class="moz-signature" cols="72">--
Cheers & Best regards,
Fei Long Wang (王飞龙)
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