Cloud Computing and SOA Convergence in Your Enterprise: A Step ...

When the Cloud Fits 33
Service-level agreements record a common understanding about services,
priorities, responsibilities, guarantees, and warranties between the cloud provider
and the cloud user. Many cloud providers do not offer them, but that
will change as larger enterprises with stricter requirements begin to leverage
cloud computing. The trend is for cloud computing providers to offer SLAs,
but of course they do so by passing the cost of the risk down to the cloud
computing platform consumer. It is another issue and cost to consider.
When the Cloud Fits
Now we understand both the benefits and the drawbacks of cloud computing.
Let’s talk more about whether or not an application or a system is a fit
for cloud computing. Keep in mind that this really begins with understanding
your own architecture issues and the design patterns of the application.
We cover these issues in much more detail in Chapter 10, “Defining Candidate
Data, Services, and Processes for the Clouds,” and Chapter 11, “Making
the Move to Cloud Computing,” but it is important that we get a sense of
where cloud computing fits before we begin the process of defining our SOA
using cloud computing.
Cloud Computing Is a Fit . . .
When the processes, applications, and data are largely independent, or
when they are not tightly coupled with other applications or information.
The idea is that if they are tightly coupled, they are difficult, if not
impossible, to decouple, and thus will not operate independently on a
remote platform. If they are loosely coupled, fit is not an issue. Loosely
coupled applications are a much better fit for cloud computing.
When the points of integration are well defined, or when there are welldefined
points within an application where that application can share
data, behavior, and processes. Thus, they are easy to integrate with applications
back in the enterprise.
When a lower level of security will work just fine, or when the information
to be contained within the cloud computing environment requires
a low level of security, and the world will not end if the information
somehow got out. Cloud computing systems typically provide “good