=Paper=
{{Paper
|id=Vol-1258/poster10
|storemode=property
|title=Framework for Dynamic Architecture Reconfiguration of Cloud Services
|pdfUrl=https://ceur-ws.org/Vol-1258/poster10.pdf
|volume=Vol-1258
|dblpUrl=https://dblp.org/rec/conf/models/Zuniga-PrietoGAI14
}}
==Framework for Dynamic Architecture Reconfiguration of Cloud Services==
https://ceur-ws.org/Vol-1258/poster10.pdf
Framework for Dynamic Architecture Reconfiguration
of Cloud Services
Miguel Zuñiga-Prieto, Javier Gonzalez-Huerta, Silvia Abrahao, Emilio Insfran
ISSI Research Group, Department of Information Systems and Computation
Universitàt Politècnica de Valencia
Camino de Vera, s/n, 46022, Valencia, Spain
{mzuniga, jagonzalez, sabrahao, einsfran}@dsic.upv.es
1 Motivation and Goals
Cloud computing is a paradigm that is transforming the way in which organization ac-
quire computational resources and is receiving more attention from the research com-
munity. The incremental deployment of cloud services is particularly important in agile
development of cloud services, where successive cloud service increments must be in-
tegrated into existing cloud service architectures. This requires dynamic reconfigura-
tion of software architectures, especially in cloud environments where services cannot
be stopped in order to apply reconfiguration changes. A model-driven architecture re-
configuration process uses models to represent architectural and technological concepts
at a high level of abstraction. Then transformations are applied on models to add the
necessary detail in order to generate specific reconfiguration operations. This demands
development efforts that could be alleviated not only by defining the models and trans-
formation sequences, but also by providing tools that facilitate tasks.
The aim of this research work is to propose a framework to facilitate the dynamic
architectures reconfiguration of cloud services, triggered by the incremental deploy-
ment of cloud services. The aforementioned aim will be satisfied by dealing with the
following sub-goals, which are:
Provide a set of tools to support the process of dynamic software architecture
reconfiguration triggered by the deployment of new cloud services.
Define transformation chains that allow to obtain platform specific reconfigura-
tion plans, starting from a high level description of how the architecture of a soft-
ware increment affect the current cloud service architecture.
In the next section, we introduce important adaptation concepts applied in this work.
2 Background information
In this section, due to space limitations, we just include the description of important
Software Adaptation Techniques applied in this framework.
Software adaptation patterns represent generic and repeatable solutions to manage
change in recurring architectural adaptation problems, and prescribe the steps needed
to dynamically adapt a software system at runtime from one configuration to another
[1]. The use of adaptation patterns is a trend to support reuse in evolution for dynamic
adaptive software architecture [2]. Adaptation of software architectures is not only sup-
ported by change management proposals, but also by proposals for solving the prob-
lems that arise when the interacting entities do not match properly. Software adaptation
promotes the generation of software adaptors to bridge incompatibilities among ser-
vices (e.g., different names of methods and services, different message ordering, etc.)
in an nonintrusive way [3,4, 5]. Generation techniques for software adaptors are begin-
ning to be used in cloud environments [6].
Cloud applications integrate and compose different cloud services. The cloud ser-
vices to be integrated may come from the delivering of a software increment in an in-
cremental development approach, or just may be product of maintenance/evolution
phases. When we refer to a software increment, we mean one or more cloud services
than are included in a software increment that need to be effectively deployed.
3 Proposed Approach and Contributions
This poster presents a model-driven framework that provides models and tools that fa-
cilitate the dynamic architecture reconfiguration activities followed during the integra-
tion of cloud services. Models allow representing high-level description of how the
Architecture of a Software Increment (ASI) affects the current cloud service architec-
ture. Transformation chains, establish how to apply consecutive transformations in or-
der to generate platform specific reconfiguration plans, obtained starting from models..
Finally, tools not only alleviate tasks of specification of models and design of transfor-
mations, but also provide dedicated services to be used during reconfiguration.
3.1 Reconfiguration Process
The process to which the proposed framework will give support aims to help software
developers during the deployment phase, on activities related to integration of software
increments into existing services in the cloud. This process supports the integration
from an architectural point of view. Its activities support the management of dynamic
reconfiguration of existing cloud services architectures, produced due to the integration
of architectural elements corresponding to the ASI. The main activities of the process
are (see Fig. 1): i) Specify Increments; ii) Check Increment Compatibility; and iii) Re-
configure Architecture. Below we present a process overview.
In the first activity, Software Architects specify the ASI as well as the impact of the
integration on the current cloud service architecture. The ASI includes: i) information
about structure and behavior of cloud services included in the software increment; ii)
information about how elements of the ASI collaborate to reconfigure the current ar-
chitecture; and iii) information about related aspects of architectures of cloud services
[7]. Next, in the following activity, Software Architects participate in verifying if the
ASI is compatible with the current cloud service architecture. If discrepancies exist be-
tween interfaces of these architectures and it is possible to solve them, Software Archi-
tects apply model-to-text (M2T) transformations to generate skeletons of Software
Adaptors specific for a cloud platform technology. Software Developers complete Soft-
ware Adaptors skeletons implementing code to solve discrepancies. Finally, in the last
activity, Software Architects participate in selecting the adaptation patterns best suited
to integrate ASI elements into the current cloud service architecture. Once the adapta-
tion patterns have been selected, Software Architects apply model transformations to
generate Reconfiguration Plan Specific of Cloud Providerthat operationalize those ad-
aptation patterns according to the ASI. In the last step of this activity Cloud Specialist,
expert in deployment, integrates the ASI into the current architecture by i) deploying
the Software Adaptors, and ii) using dedicated services to apply the Reconfiguration
Plan Specific of Cloud Provider in corresponding cloud platform. The integration, dy-
namically reconfigures instances of the running Actual System Architecture.
Design SLA Current Actual System Adaptation Cloud-Platform
Artifacts Architecture Architecture Pattern Specific Adaptation
Model Repository Operations
in
in In-out
in in In-out in in
1 2 3
Is Compatible? Yes
Specify Check Increment Reconfigure
2
Compatibility
Increments No Architecture
out
guide out
out
Increment
Description
Gudelines Cloud Reconfiguration Plan
Increment Adaptors Specific of Cloud
Architecture Model Provider
Fig. 1. Overview of the reconfiguration process
3.2 Increment Description Language
To support the first activity of the dynamic architecture reconfiguration process (see
Section 3.1), this framework provides to Software Architects a specialized language to
specify the architecture of the software increment. We call it Increment Description
Language (IDL). Service Oriented Architecture Modeling Language (SoaML)[8] lev-
erages Model Driven Architecture (MDA) and provides a UML profile and meta-model
for the specification of services. However, SoaML does not allow to represent how the
architecture of a software increment affects the existing cloud architecture nor to spec-
ify information related to cloud software architectures. IDL is a Domain-Specific Lan-
guage (DSL) that extends SoaML, so IDL meta-model extends the SoaML meta-model
using stereotypes to point out the way in which each element of ASI impacts on current
cloud service architecture. Furthermore, we use tagged values to specify information
related to cloud software architectures.
3.3 Transformation Chains
To support the second and third activity of the dynamic architecture reconfiguration
process (see Section 3.1), this framework identify a set of models and transformation
chains (consecutive transformations) that must be applied to those models. This, in or-
der to generate platform specific reconfiguration plans, obtained starting from a high-
level description of how the architecture of a software increment affects the current
cloud service architecture.
4 Contributions
A framework for dynamic architecture reconfiguration that properly combines Model-
Driven and Software Adaptation Techniques represents an important step towards the
incremental and dynamic deployment of cloud services into existing cloud service ar-
chitectures.
The first contribution is an Increment Description Language that allows Software
Architects to specify the architecture of the software increment. They will be able to
specify architecture reconfiguration operations (e.g., add service, add connector, etc.)
using a high-level abstraction language. To put it another way, when a Software Archi-
tect specifies the impact of ASI on current architecture, what he/she is really doing is
specifying architecture reconfiguration operations at a high-level of abstraction.
The second contribution is the definition of Transformation Chains, used to: i) pro-
mote compatibility between the architecture of the increment with the existing cloud
architecture; ii) generate a Reconfiguration Plan Specific of Cloud Provider that applies
adaptation patterns to reconfigure existing cloud architecture.
Finally, in order to achieve reconfiguration we provide dedicated services. These
services use the information of reconfiguration plans to dynamically reconfigure in-
stances of the running Actual System Architecture.
5 Related work
Software evolution based on reconfiguration of software architectures is an active area
of research; however, there are gaps that still need to be covered. Jamshidi et al. [2],
identified a relative lack of contributions for runtime evolution as well as frameworks
to support the reconfiguration process. They found lack of support during the integra-
tion and provisioning stage as well as during deployment stage. In our work, we give
support to the dynamic reconfiguration of software architectures in the deployment
stage of the software life cycle.
In this section, due to space limitations, we detail the gaps we found in most relevant
related works [9, 10, 11]. Baresi et al.[9], MOdel-based SElf-adaptation of SOA sys-
tems (MOSES) [10], and Self-architecting Software Systems (SASSY) [11]. These
works i) take into account structural and behavioral aspects for reconfiguration; ii) use
SLA or QoS negotiation to discover and select the more suitable service implementa-
tion (instance); and iii) apply dynamic binding for reconfiguration. This means that
reconfiguration improves non-functional properties through perfective changes. How-
ever, adaptive changes (e.g., software increments due to new functionalities) that may
require architecture reconfiguration are not taken into account. They also abstract mod-
els of business requirements or derive high level architectures; however, they do not
take into account the importance of architectural aspects in incremental development
processes [12]. Despite the fact that the cited approaches propose consistency or com-
patibility checking tasks, they do not provide solutions to support deployment on
changing cloud platforms. In addition, those who propose frameworks or support ar-
chitecture specification do not consider the architecture of the increment as an inde-
pendent entity.
Acknowledgments. This research was supported by the Value@Cloud project
(MICINN TIN2013-46300-R); the Scholarship Program Senescyt, Ecuador; the Fac-
ulty of Engineering, University of Cuenca, Ecuador; and the ValI+D program
(ACIF/2011/235), Generalitat Valenciana.
6 References
1. Gomaa, H., Hashimoto, K., Kim, M., Malek, S., Menascé, D.: Software Adaptation Patterns
for Service-Oriented Architectures. ACM Symposium on Applied Computing. pp. 462–469.
ACM, New York (2010).
2. Jamshidi, P., Ghafari, M., Ahmad, A., Pahl, C.: A Framework for Classifying and
Comparing Architecture-Centric Software Evolution Research. 17th European Conference
on Software Maintenance and Reengineering. pp. 305–314. IEEE, Genova (2013).
3. Canal, C., Poizat, P., Salaun, G.: Model-Based Adaptation of Behavioral Mismatching
Components. Softw. Eng. IEEE Trans. 34, 546–563 (2008).
4. Yellin, D.M., Strom, R.E.: Protocol Specifications and Component Adaptors. ACM Trans.
Program. Lang. Syst. 19, 292–333 (1997).
5. Becker, S., Brogi, A., Gorton, I., Overhage, S., Romanovsky, A., Tivoli, M.: Towards an
Engineering Approach to Component Adaptation. Springer Berlin Heidelberg (2006).
6. Miranda, J., Guillen, J., Murillo, J.M., Canal, C.: Assisting Cloud Service Migration Using
Software Adaptation Techniques. 6th Int. Conf. on Cloud Computing. pp. 573–580 (2013).
7. Hamdaqa, M., Livogiannis, T., Tahvildari, L.: A Reference Model for Developing Cloud
Applications. CLOSER. pp. 98–103. Citeseer (2011).
8. Object Management Group: Service Oriented Architecture Modeling Language (SoaML),
http://www.omg.org/spec/SoaML/.
9. Baresi, L., Heckel, R., Thöne, S., Varr´o, D´.: Style-Based Modeling and Refinement of
Service-Oriented Architectures. Softw. Syst. Model. 5, 187–207 (2006).
10. Cardellini, V., Casalicchio, E., Grassi, V., Lo Presti, F., Mirandola, R.: QoS-Driven Runtime
Adaptation of Service Oriented Architectures. Proc. 7th Jt. Meet. Eur. Softw. Eng. Conf.
ACM SIGSOFT Symp. Found. Softw. Eng. 131–140 (2009).
11. Menascé, D.A., Gomaa, H., Malek, S., Sousa, J.P.: SASSY: A Framework for Self-
Architecting Service-Oriented Systems. Software, IEEE. 28, 78–85 (2011).
12. Babar, M.A., Brown, A.W., Mistrik, I.: Making Software Architecture and Agile
Approaches Work Together: Foundations and Approaches. Agile Software Architecture:
ligning Agile Processes and Software Architectures. pp. 1–22. Morgan Kaufmann (2013).