<p>Can someone tell me use cases that uses custom metrics to scale and the reason for using that?</p>
<p>i have heard some application uses custom application metrics to scale, why cant we just use cpu metrics ?</p>

<p>Sometimes you also would like to scale based on external factors, for instance:</p>
<ul>
<li>scale based on the number of messages in a queue</li>
<li>scale based on the incoming traffic in another service</li>
</ul>
<p>so you can predict an increase in your traffic and be preventive instead of reactive to the load.</p>
<p>Also no long time ago the scale based on memory consumption was not accurate so this used to be another use case.</p>
