Selecting a Service Platform - The Practice of Cloud System Administration - page 47

Chapter 3. Selecting a Service Platform
When I hear someone touting the cloud as a magic-bullet for all computing prob-
lems, I silently replace “cloud” with “clown” and carry on with a zen-like smile.
—Amy Rich
A service runs on a computing infrastructure called a platform. This chapter provides an
overview of the various types of platforms available in cloud computing, what each of them
provides, and their strengths and weaknesses. It does not offer an examination of specific
products but rather a categorization that will help you understand the variety of offerings.
Strategies for choosing between these different services are summarized at the end of the
chapter.
Theterm“cloud”isambiguous;itmeansdifferentthingstodifferentpeopleandhasbeen
made meaningless by marketing hype. Instead, we use the following terms to be specific:
• Infrastructure as a Service (IaaS): Computer and network hardware, real or virtu-
al, ready for you to use.
• Platform as a Service (PaaS): Your software running in a vendor-provided frame-
work or stack.
• Software as a Service (SaaS): An application provided as a web site.
Figure 3.1 depicts the typical consumer of each service. SaaS applications are for end users
and fulfill a particular market niche. PaaS provides platforms for developers. IaaS is for op-
eratorslookingtobuildtheirownplatformsonwhichapplicationswillbebuilt,thusprovid-
ing the most customizability.