An overview of Auto Scaling

We have been talking about AWS and the concept of dynamic scalability, also known as Elasticity in general throughout this book; well now is the best time to look at it in depth with the help of Auto Scaling!

Auto Scaling basically enables you to scale your compute capacity (EC2 instances) either up or down, depending on the conditions you specify. These conditions could be as simple as a number that maintains the count of your EC2 instances at any given time, or even complex conditions that measure the load and performance of your instances such as CPU utilization, memory utilization, and so on. But a simple question that may arise here is why do I even need Auto Scaling? Is it really that important? Let's look at a dummy application's load and performance graph to get a better understanding of things; let's take a look at the following screenshot:

The graph to the left depicts the traditional approach that is usually taken to map an application's performance requirements...