scenario is rather like an apartment: You rent the space and decorate and
configure it as you like, within structured guidelines. Some examples of PaaS
include the Google App Engine, raw compute nodes used to scale services,
and social application platforms like Facebook.
Infrastructure as a Service (IaaS)
IaaS goes even further than PaaS. In this service model, you transition your
entire server to the cloud. Your provider offers computers, typically virtual
ones, on which you can install any operating system (perhaps within a set
menu the provider allows), and you can configure it as you like. Someone else
takes care of the physical machines and networks, and you take care of all the
rest. IaaS is like buying a condominium: You own it and can do whatever you
want inside it, but someone else takes care of the grounds and landscaping.
Metal as a Service (MaaS)
Generally, the only other step available beyond IaaS is traditional server
building, where you are responsible for the physical machine and everything
on it. However, Ubuntu has added another service to the list: metal as a
service (MaaS), which is designed to bring the language of the cloud to
physical servers. Their goal is to make it as easy to set up the physical
hardware, deploy your app or service, and scale up or down dynamically as it
is in the cloud. The server is installed on the physical hardware and then
managed using one web interface to manage all the various machines. The
section “Ubuntu Metal as a Service (MaaS),” later in this chapter, is dedicated
to this topic.
Things to Consider Before You Make any Decisions
You don’t have to create your own cloud infrastructure, but you can. You can
also deploy Ubuntu to cloud providers such as Microsoft Azure or Amazon
Web Services (AWS). Before you do anything like this, though, you need to
carefully consider what your needs are and decide what sort of service(s) you
need. Do you just want to run a web application on someone else’s already-
set-up server, or do you want to set up a system for scalable computing where
additional Hadoop nodes can be added and removed at will when big jobs
start and end? Only you know the answers to such questions. When you have
it all figured out, you can seek your solution and can think about how you can
use Ubuntu to set it up. This chapter describes many options, but you are the