Selecting a Service Platform - The Practice of Cloud System Administration - page 61

3.3.3 Cost
Thecostofusingapubliccloudmayormaynotbelessthanthecostofbuildingtheneces-
sary infrastructure yourself. Building such infrastructure requires large amounts of engin-
eering talent, from physical engineering of a datacenter's cooling system, electric service,
and design, to technical expertise in running a datacenter and providing the services them-
selves. All of this can be very expensive. Amortizing the expense over many customers
reduces cost. By comparison, doing it yourself saves money due to the benefits of vertic-
al integration . Vertical integration means saving money by handling all levels of service
delivery yourself, eliminating the uplift in cost due to “middle men” and service provider
profit margins. There is a break-even point where vertical integration becomes more eco-
nomical. Calculating the total cost of ownership (TCO) and return on investment (ROI)
will help determine which is the best option.
Deciding whether the cost of private versus public clouds is appropriate is similar to
makingarentversusowndecisionaboutwhereyoulive.Inthelongterm,itislessexpens-
ive to own a house than to rent one. In the short term, however, it may be less expensive
to rent. Renting a hotel room for a night makes more sense than buying a building in a city
and selling it the next day.
Similarly, building a private cloud makes sense if you will use all of it and need it for
as long as it takes to pay for itself. Using a third-party provider makes sense if the need is
small or short term.
3.3.4 Control
A private cloud affords you more control. You can specify exactly what kind of hardware
will be used, which network topology will be set up, and so on. Any feature you need is
a matter of creating it yourself, acquiring it, or licensing it. Changes can happen as fast as
yourorganizationcanmakethem.Inapubliccloudyouhavelesscontrol.Youmustchoose
from a finite set of features. While most providers are responsive to feature requests, you
are merely one customer among many. Providers need to focus on those features that will
be used by many customers and may not be able to provide the specialized features you
need.
Lettingthevendortakecareofallhardwareselectionmeanslosingtheabilitytospecify
low-level hardware requirements (specific CPU types or storage products).