Merging of TOSCA Cloud Topology Templates - IAAS

1 Introduction
1 Introduction
Cloud Computing is a new paradigm discussed in research, the IT industry and beyond [5],
[20]. It brings the no longer recent goal [36] of computing resources being available as utilities
comparable to gas, water or electricity closer to reality. It has the potential of “creative
destruction” that destroys an old economic structure and creates a new one [44]. The potential
lies in the use of computing resources as pay-per-use services that scale on demand and
enable organizations to invest more into their core competences than into building and
maintaining IT systems.
However, without the standardization of Cloud Computing there is the danger of vendor
lock-in for its users. Once a particular Cloud Computing provider relying on proprietary
approaches is chosen it may be difficult to obtain computing services from a different provider
[5], [30]. The Topology and Orchestration Specification for Cloud Applications
(TOSCA) provides a standardization approach enabling portability of cloud services between
different Cloud Computing providers [32]. TOSCA is an XML-based language and
metamodel whose grammar provides the possibility to describe IT services. The main goal
of the TOSCA specification is to enable a cloud provider and environment independent description
of these services concerning structure and management aspects during their life
cycle. TOSCA specifies so-called Service Templates whose structure is described by a Topology
Template. Plans located in a Service Template provide the possibility to manage the
service instances during run-time. They contribute to the (semi-) automatic creation and
management of IT services as suggested by the cloud computing paradigm [6]. Ultimately,
the definition of the topology and orchestration plans as interoperable artifacts are supposed
to make IT services exchangeable between different cloud providers.
1.1 Problem Statement
The TOSCA specification provides means to model enterprise applications in a standardized
way. In view of mergers and acquisitions, data center consolidation, for breaking up silo
structures in IT departments and for support of modeling experts it is necessary to find concepts
for analyzing already modeled TOSCA Topology Templates for similar elements and
for unifying these elements and, thus, two Topology Templates.
The goals of this master’s thesis are the following: (1) the development of a matching concept
for finding corresponding elements inside and between two Topology Templates by
systematically exploring all different constellations TOSCA elements can take. Additionally
appropriate algorithms implementing the concept have to be formulated. (2) the matching
concept and algorithms are the prerequisite for developing a concept and corresponding
algorithms that merge the TOSCA elements that have been identified as compatible. (3) All
the findings of goal (1) and (2) are incorporated into an extendable framework named
TOSCAMerge framework that is implemented prototypically using the programming language
Java. (4) the last goal is the creation of a set of example TOSCA Service Templates to
evaluate the prototype framework and the researched concepts.
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