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

110 Chapter 6 Working from Your Services to the Clouds
same applications and services but never give up the ability to leverage these
systems and services. Services are typically location and platform independent.
This means that no matter where the services exist, on-premise or cloudbased,
they are accessible as if they were local.
In many architectural systems, we would create new services as part of
the services model. This book looks at methods to extend an SOA to cloud
computing if that approach make sense. Thus, we limit our discussion to
identifying existing services, documenting those services, and relocating
those services if cost justified. Keep in mind that you could be building new
services as part of this process.
Again, the ability to address all of these systems through services provides
the architect with the ability to access the underlying application behavior
and information as if the application and services were native and
local. The use of services provides location independence, meaning you can
leverage services no matter where they exist. A single application could be
made up of dozens of services hosted in a dozen different locations, onpremise
and in the clouds. This is why we use services within the context of a
widely distributed system, including an SOA using cloud computing.
Since they all expose information and behaviors as services, which
typically use a common and standard interface such as Web Services, they are
location independent (cloud or on-premise), platform independent, programming
language independent, and user interface independent—that is, if
they are properly created.
Continuing with our case study from Chapter 5, “Working from Your
Data to the Clouds,” Blue Mountain Hammocks, or BMH, has
A sales automation system that uses Oracle as the database, with the
application built in C++. This application is also connected to BMH’s
online store.
An open source inventory management system built using Java and
MySQL.
A general ledger system that uses a packaged accounting system built
using dBase, a PC-based database.
They all run on different hardware and software platforms, on-premise.
BMH wants to understand its architecture and potentially move pieces
of it to cloud computing. We already obtained a data-level understanding
when we created the information model in Chapter 5.