title: AWS Auto Scaling Group - Application Load Balancer Request Count Per Target
body: <p>On AWS, you can create an auto scaling policy which scales based on "Application Load Balancer Request Count Per Target". </p>
  
  <p><strong>Like this</strong>:</p>
  
  <p><a href="https://i.stack.imgur.com/zXizr.png" rel="noreferrer"><img src="https://i.stack.imgur.com/zXizr.png" alt="enter image description here"></a></p>
  
  <p>This has a min of 1 instance and a max of 5. It should aim to achieve 10 "Request count per target" for my ElbTargetGroup.</p>
  
  <p>My question is, what is "Application Load Balancer Request Count Per Target"? </p>
  
  <p>Is this:</p>
  
  <ul>
  <li>Number of active connections to targets from the load balancer divided by number of targets?</li>
  <li>Number of requests per 5 minutes divided by number of targets?</li>
  <li>Number of requests per 1 minute divided by number of targets?</li>
  </ul>
  
  <p>The documentation <a href="http://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-cloudwatch-metrics.html" rel="noreferrer">here</a> just says:</p>
  
  <blockquote>
    <p>The average number of requests received by each target in a target group. You must specify the target group using the TargetGroup dimension.</p>
  </blockquote>
  
  <p>Also, how long does it have to be over that target for it to start creating new instances? The main reason I ask is that I have sent many requests to this load balancer, but scaling events aren't being triggered.</p>