Azure ConstraintRules not working

Question

I am deploying a very simple Azure cloud service.

Trying to get Autoscaling working so I can schedule scaling up/down depending on time of day.

Have everything installed and configured, deploys to Azure without any issues however my rules don't seem to be being adhered to.

Currently I have the following, which I would expect service to run at a minimum of 2 instances but it always stays at 1.

<rules xmlns="http://schemas.microsoft.com/practices/2011/entlib/autoscaling/rules" enabled="true">
  <constraintRules>
    <rule name="Default" description="Default rules" enabled="true" rank="1">
      <actions>
        <range min="2" max="8" target="MyRoleName"/>
      </actions>
    </rule>
  </constraintRules>
</rules>

Feel like I'm missing something really simple but unsure what?

Thank you

Answer 1

AFAIR from my Wasabi experience - constraint rules without timetable will not be run by service at all - they have no dedicated trigger conditions. It purpose is to limit max and min number of instances - so reactive rules will not be able to over-provisioning (this could lead to higher-than-planned expenses) and under-provisioning your service instances (this could lead to Azure SLA requirements violation).

I think you should read this article about proper way to setup schedule-based autoscaling for your service. In short - you need timetable section for you rule. Something like that (shameless rip from mentioned link)

<rules xmlns="http://schemas.microsoft.com/practices/2011/entlib/autoscaling/rules" enabled="true">
  <constraintRules>
    <rule name="Default" description="General Limitation" enabled="true" rank="1">
      <actions>
        <range min="2" max="8" target="MyRoleName"/>
      </actions>
    </rule>

    <rule name="Peak" description="Active at peak times" enabled="true" rank="100">
      <actions>
        <range min="4" max="4" target="MyRoleName"/>
      </actions>
      <timetable startTime="08:00:00" duration="02:00:00">
        <daily/>
      </timetable>
    </rule>
  </constraintRules>
</rules>