To Grasp the Cloud—Fundamental Concepts - Deploying and Managing a Cloud Infrastructure - page 44

these workstations was another nightmare, and enabling support for updated enterprise apps
would often require implementations spanning over several weeks.
With downsizing of IT departments across enterprises, a lazy model of individual
workstation deployment would simply not work. This is where VDI comes in. It enables
enterprises to consolidate workstations into a single data center where all the hardware
resources and OS instances are managed, and workstations across the enterprise are con-
nected to a single or multiple data centers, often spread over different physical locations
for large enterprises.
Some of the key features of VDI are described in the sections that follow.
Rapid Deployment
With VDI, OS instances—for example, Windows 8—are available through “images,”
which are preconfigured and enterprise app ready. IT administrators can fire up a new OS
instance for any given workstation with the image already available in the data center. This
whole process of firing up and winding down OS instances takes no more than a minute,
and it can be repeated for every workstation within the enterprise.
Centralized Management
Previously, with the individual deployment model, managing workstations (which included
troubleshooting, upgrades, and configuration) would require significant human time. With
the VDI model, a single OS image can be deployed on thousands of VMs and fired up for
every single workstation within the enterprise. When updates are rolled out or modifications
are made to configurations for specific enterprise apps, a single image can be updated and
rolled out for every VM running without the need to manually touch the workstation. This
tremendously increases IT administrator efficiency and productivity.
Upfront and Incremental Costs
Compared to rolling out individual workstations, the initial data center setup cost would
be significantly more than it would cost to setting up individual workstations, but this cost
balances out when workstations scale out because incremental costs would be minimal.
Infrastructure as a Service
With Desktop as a Service (DaaS), on-premises desktop machines connect to VMs running
within the enterprise data center. In contrast to DaaS, the IaaS model is for enterprises as well
as cloud providers to enable infrastructure resources on demand in-house as well as enable
third-party developers to deploy their applications. IaaS is part of three key offerings of the
cloud, the other two being Platform as a Service (PaaS) and Software as a Service (SaaS). In
the IaaS model, hypervisors play the key role of virtualizing the compute, storage, and net-
working components of a data center and managing the complete life cycle of VMs (creation,
management/monitoring, and deletion). Both Type 1 and Type hypervisors can be used to
implement an IaaS solution depending on the end-user needs and business model.
There are three main verticals where IaaS is implemented, discussed in the following
sections.