eCommerce in the Cloud

Chapter 4. Auto-Scaling in the Cloud

What Is Auto-Scaling?

Auto-scaling, also called provisioning, is central to cloud. Without the elasticity provided by auto-scaling, you’re back to provisioning year-round for annual peaks. Every ecommerce platform deployed in a cloud should have a solution in place to scale up and down each of the various layers based on real-time demand, as shown in Figure 4-1.

Figure 4-1. Benefits of an auto-scaling solution

An auto-scaling solution is not to be confused with initial provisioning. Initial provisioning is all about getting your environments set up properly, which includes setting up load balancers, setting up firewalls, configuring initial server images, and a number of additional one-time activities. Auto-scaling, on the other hand, is focused on taking an existing environment and adding or reducing capacity based on real-time needs. Provisioning and scaling may ultimately use the same provisioning mechanisms, but the purpose and scope of the two are entirely different.

The goal with auto-scaling is to provision enough hardware to support your traffic, while adhering to service-level agreements. If you provision too much, you waste money. If you provision too little, you suffer outages. A good solution will help you provision just enough, but not so much that you’re wasting money.

In this chapter, we’ll cover what needs to be provisioned, when to ...