AWS EC2 Auto Scaling Groups: I get Min and Max, but what's Desired instances limit for? : <p>When you setup an Auto Scaling groups in AWS EC2 <code>Min</code> and <code>Max</code> bounds seem to make sense:</p>

<ul>
<li>The minimum number of instances to scale down to based on policies</li>
<li>The maximum number of instances to scale up to based on policies</li>
</ul>

<p>However, I've never been able to wrap my head around what the heck <code>Desired</code> is intended to affect.</p>

<p>I've always just set <code>Desired</code> equal to <code>Min</code>, because generally, I want to pay Amazon the minimum tithe possible, and unless you need an instance to handle load it should be at the <code>Min</code> number of instances.</p>

<p>I know if you use <code>ElasticBeanstalk</code> and set a <code>Min</code> to 1 and <code>Max</code> to 2 it sets a <code>Desired</code> to 2 (of course!)--you can't choose a value for <code>Desired</code>.</p>

<p>What would be the use case for a different <code>Desired</code> number of instances and how does it differ?  When you expect AWS to scale lower than your <code>Desired</code> if desired is larger than <code>Min</code>?</p>
