Virtualization

Virtualization is a technology that system administrators have been using in our datacenters for years, and it is at the heart of cloud computing infrastructure. It is a technology that allows the physical resources of a computer (CPU, RAM, hard disk, graphics card, etc.) to be shared by virtual machines (VMs). Consider the old days when a single physical hardware platform—the server—was dedicated to a single‐server application like being a web server. It turns out that a typical web server application didn't utilize much of the underlying hardware resources available to it on the server. For purposes of this discussion, let's assume that a web application running on one of our physical servers utilized 30 percent of the hardware resources. That meant that 70 percent of the physical resources were going unused; thus, the server was being underutilized.

With virtualization, we could now install three web servers by using VMs each utilizing...