Principles, Methodology and Tools for Engineering Cloud Computing Systems - Advanced Design Approaches to Emerging Software Systems - page 254

2.1 Service Development,
Deployment and Composition,
Testing and Maintenance

intermediate parts or components, and the
transportation of all components to the
right place.

• Market mediation function ensures that the

variety of products reaching the market-
place matches what customers want.

The Cloud is a powerful tool for application
developers. It frees them from the complexity of
infrastructure management (provision and scaling
of hardware resources and tools), and simplifies the
access to the services that the application requires.
These services can be provided out-of-the-box by
the Cloud platform itself, or accessed remotely
through well known interfaces and protocols.
Depending on the type of cloud, services have
a different lifecycle. As mentioned above, Clouds
are categorized in three groups. Thus, each service
can have a different lifecycle, and no support is
supplied by the cloud to enforce it. Likewise,
SaaS clouds do not implement the concept of
'user service lifecycle', but for a different reason:
users cannot run their own services on them, so
it makes not sense to define a lifecycle for them.
Thus, this section deals with services lifecycle in
PaaS platforms, as they do define the different
stages of users services, usually deployed as one
or more components running in the PaaS container.
In Figure 2, we show a schematic view of Plat-
form as a Service (PaaS) Clouds, which run the
software components (modules) of the deployed
services. A service can be composed by one or
several of these components. This Figure further
develops the PaaS elements shown in the “Cloud
stack” presented in (Lenk et al. 2009). Please keep
in mind that this Figure does not depict a standard
architecture of PaaS clouds. It only shows the
different 'functional units' that can be expected
in typical PaaS platforms. Such architecture is
strongly dependent on how the Cloud provider
decides to implement the container, framework
and functionalities (for control, monitoring, etc.)
supplied.
The core element of the PaaS platform is the
Container , which provides a runtime for the
software components (modules) of the service.
Also, the Cloud will offer Cloud Services that

While for functional products the physical
function dominates, the market mediation function
is more important than the physical function for
innovative products. (Paulitsch, M. 2003) Here
again the mixed characteristics of the C-SC lead to
a high importance of the physical function, as this
is the core product of Cloud Services, but more so
the need for a strong market mediation function
arises from the modular design of these services.
The major aim of this chapter is to highlight the
relevant stages of service production lifecycle and
align them with some of the most relevant recent
approaches applied to Cloud environments. The
reader should note that the efforts here highlighted
are not unique and a detailed comparison is not
herein provided, although the referenced papers
immediately lead to most relevant systems and
provide readers with that comparison. Hereby,
the various stages a service runs through dur-
ing its lifetime have to be followed, monitored
and finally managed. The following section will
describe service lifecycle management in Cloud
environment and will give detailed technical ap-
proaches on this core management functionality.

2. SERVICE LIFECYCLE
MANAGEMENT IN CLOUD
ENVIRONMENTS 1

This section will deal with all the different stages
a “cloudified” service goes through during its
lifecycle. All the subsections should provide
state of the art and challenges, showing current
principles, methodology and tools.