ATHABASCA UNIVERSITY

INTEROPERABILITY CHALLENGES WITH CLOUD COMPUTING

BY

PIOTR M. NOWAK

A project submitted in partial fulfillment

of the requirements for the degree of

MASTER OF SCIENCE in INFORMATION SYSTEMS

Athabasca, Alberta

March, 2014

© Piotr Nowak, 2014

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DEDICATION

This project is dedicated to my parents who have continued support my pursuit of education.

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ABSTRACT

The research described interoperability challenges between different cloud providers and

analyzed the various standards that could help achieve cooperation between clouds. Despite

the identification of the many benefits of cloud properties (including elasticity, accessibility

and flexibility to users) it continued to be limited to one cloud provider. The interoperability

between cloud environments was seen as an issue with the development of proprietary

solutions by cloud providers. In order to enable the end users to freely select cloud services

and products from one cloud to another, a standardized approach was deemed necessary. The

study analyzed multiple research articles related to interoperability challenges in cloud

computing environments. This essay described the most popular standards that have been

designed to achieve cloud interoperability. The standards, such as Open Virtualization

Format (OVF), Cloud Data Management Interfaces (CDMI), Open Cloud Computing

Interface (OCCI), Cloud Infrastructure Management Interface (CIMI) and Service-Oriented

Architecture (SOA) framework were categorized by the cloud service models. The research

constructed and evaluated two hypotheses: “If an Open Virtualization Format helps to

achieve the virtual machine portability then the implementation of OVF would solve the

problem of the virtual machine migration from one cloud provider to another” and “If a

Service-Oriented Architecture helps to solve the problem of software as a service

interoperability, then the use of SOA would resolve the interoperability problems with the

SaaS model of cloud computing”. The study used different research methods to analyze the

standards and to provide recommendations. The association analysis and causal inferencing

research methods were used to analyze the standards and to evaluate the hypotheses. The

study was performed using a meta-analysis research method. The research pointed out the

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issues and challenges related with cloud interoperability. Additionally, the essay compared

the portability of the software in traditional computing system versus cloud computing. The

study presented the future trends of migrating e-learning systems to cloud computing

platforms. The research summarized the findings and made suggestions for further research.

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ACKNOWLEDGMENTS

Thanks to Dr. Qing Tan for his tutoring and supervision of this research, and to Athabasca

University for the provisioning of the Master of Science in Information Systems program.

I wish to thank my fellow postgraduate students who I was able to work, collaborate with and

learn from on different group projects and courses throughout the program.

Special thanks to Jennifer Bawden for her support and help in reviewing this research essay.

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TABLE OF CONTENTS

CHAPTER I - INTRODUCTION ............................................................................. 1

Research purpose and objectives .......................................................................... 2

Research questions and hypotheses ...................................................................... 2

Research methodologies ....................................................................................... 4

Research scope and limitations ............................................................................. 5

Research contribution ........................................................................................... 6

CHAPTER II - REVIEW OF RELATED LITERATURE .................................... 7

Interoperability issues with cloud computing ....................................................... 7

The importance of standards in cloud computing ................................................. 9

Standards that can help solve interoperability issues .......................................... 10

Service-Oriented Architecture and cloud computing ......................................... 17

CHAPTER III - METHODOLOGY ....................................................................... 19

The cloud computing concept ............................................................................. 20

Cloud standardization initiatives......................................................................... 23

Cloud standards analysis ..................................................................................... 26

Service-Oriented Architecture and cloud computing analysis ............................ 32

The hypotheses evaluation .................................................................................. 35

CHAPTER IV - ISSUES, CHALLENGES AND TRENDS .................................. 37

Issues and challenges with the cloud interoperability......................................... 37

Software portability in the cloud versus traditional computing system .............. 39

Trends of migration of e-learning platforms into cloud computing ................... 41

CHAPTER V - CONCLUSIONS AND RECOMMENDATIONS ....................... 44

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Conclusions ......................................................................................................... 44

Recommendations for further research ............................................................... 46

REFERENCES .......................................................................................................... 47

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LIST OF TABLES

Table I. Summary of groups involved in standard cloud creation. ............................. 24

Table II. Summary of functionalities of OVF, OCCI, CDMI standards..................... 29

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LIST OF FIGURES

Fig. 1. Cloud computing architecture. ........................................................................ 21

Fig. 2. Cloud computing resource allocation. ............................................................. 22

Fig. 3. The cloud storage reference model using CDMI. ............................................ 27

Fig. 4. The OCCI boundary protocol in cloud provider’s architecture. ...................... 28

Fig. 5. The SOA Reference Architecture. ................................................................... 34

Fig. 6. Increasing interoperability issues in cloud models. ......................................... 38

Fig. 7. Portability of applications in traditional computing system. ........................... 40

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CHAPTER I

INTRODUCTION

The concept of cloud computing has grown in popularity as a result of virtualization and

web service oriented architecture. The cloud computing paradigm provides infrastructure,

platform and software as a service to clients. Although the concept of cloud computing is

versatile, interoperability challenges still exist among different cloud computing

implementations.

Cloud computing interoperability generally refers to the ability to migrate services or to

move data from one provider to another. As cloud providers design their own proprietary

solutions to manage and monitor resources in clouds, interoperability between the cloud

environments continues to be an issue. A standardized approach is necessary in order to

enable the end user to freely select and distribute services from one cloud to another.

There are different options and concepts proposed by research groups to achieve cloud

interoperability. Reaching industry consensus is not a simple task. Further research and

discussion are needed.

Cloud computing should provide users with the full benefits of cloud properties

including elasticity, scalability, accessibility, and flexibility, and should not limit it within

only one particular cloud provider. There are different protocols, standards, and concepts

available that target cloud interoperability problems. True cloud interoperability benefits are

being recognized by clients and will be needed to be implemented sooner rather than later.

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Research purpose and objectives

The objective of the research was to describe, analyze and validate the impacts of the

various standards of interoperability issues that exist today with cloud computing. This

research essay, interoperability challenges with cloud computing, described issues that exist

between cloud environments and also reviewed different solutions currently available that

could help achieve cooperation between different cloud computing platforms. The study was

performed using a meta-analysis research method. It used different techniques to analyze and

to evaluate standards. The standards used to achieve interoperability with clouds were

categorized by the cloud service model.

This meta-analysis research essay brought together several studies and verified the

results in a systematic review that could be used for further research.

Research questions and hypotheses

Research questions were created in order to comprehend the research problem and to

determine if the current proposed standards could help to achieve interoperability with cloud

computing. In order to better understand the phenomenon of the subject, some preliminary

questions were created such as:

What are the interoperability problems with cloud computing?

What standards can be implemented in cloud computing in order to help solve the

issue of interoperability?

Once the initial questions were answered and the problem was understood, further questions

could be asked regarding technology related to interoperability between clouds. Because

cloud computing uses a web service framework, some important questions should be asked

such as:

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What are the effects of Service-Oriented Architecture (SOA) on the interoperability

with the cloud computing environment?

How software portability differs in the cloud as compare to the traditional computing

system?

Although there are numerous articles related to cloud computing and cloud services, the

interoperability challenges are still not widely analyzed and described.

After analyzing the problem of interoperability in cloud computing, the following

hypotheses were constructed in an alternative form (HA):

As an If, then statement;

First hypothesis:

“If an Open Virtualization Format helps to achieve the virtual machine portability

then the implementation of OVF would solve the problem of the virtual machine

migration from one cloud provider to another.”

Second hypothesis:

“If a Service-Oriented Architecture helps to solve the problem of software as a

service interoperability, then the use of SOA would resolve the problems with

interoperability in the SaaS model of cloud computing.”

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Research methodologies

The research was performed using a meta-analysis research method. Data was collected

from different research articles and studies. The reference material used in this essay to

support the research came from scholarly articles, journals, and publications published by the

Institute of Electrical and Electronics Engineers (IEEE) and/or the Association for

Computing Machinery (ACM). The literature covered the period from 2008 to 2013 and was

researched using the Athabasca University Digital Library. The essay reviewed industry

standards available to help solve interoperability problems between clouds.

The research included an analysis of the data association between collected standards

and their roles. The association analysis in this research worked based on the relationship

between dependent variables (data migration, workload management, migration of virtual

machines) and independent variables (standardized migration protocols, standardized

management interfaces, Open Virtualization Format). Analyzing trends and relationships

allowed for the establishment of association rules. In this research, knowing the association

rules or patterns was helpful to support the hypotheses as well as to provide a conclusion on

the impacts that standards have on the interoperability issues among the cloud environments.

The study used various research methods to obtain, assess, analyze and evaluate the

gathered data. The research used the process of causal inference in order to analyze the

relationship between the cause and effect. In other words, it was finding the reason why

something had happened and what had caused it to occur. In order to make a conclusion or

recommendation, multiple actions were compared using causal effect reasoning. The

difference between causation and association was a key part in the comprehension of causal

inferencing. For example, the hypothesis that Service-Oriented Architecture (SOA) helps to

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achieve interoperability among clouds might seem as though interoperability was associated

with the SOA paradigm, however, it was not the case in either relationship or association. It

was a causal effect of how the SOA was implemented in order to achieve interoperability

between different cloud providers. This research used the causal inferencing process to

analyze and evaluate the hypothesis “If SOA helps achieve the problem of interoperability,

then the use of SOA would solve the interoperability problem with cloud computing”.

Research scope and limitations

The research focused on categorizing the interoperability issues based on cloud

operation, functionality, tools, and technology. The essay used multiple techniques and

approaches to gather information, analyze, evaluate and to provide recommendations. The

research evaluated the hypothesis by using a causal effect reasoning research method.

The essay emphasized the problems of interoperability among different cloud providers.

It also presented various approaches in order to solve the problem of interoperability with

clouds. The research summarized the most current and promising solutions that could be used

for further research, to ease the multi cloud cooperation.

The research described the findings of different protocols, standards, and tools used to

help solve the problem of interoperability. It detailed the implications and issues related to

cloud interoperability. Finally, the essay described new trends as well as proposed further

research in order to achieve cloud interoperability. The research may have a limited life span

as cloud computing is a fast evolving technology and new tools and standards are continually

being introduced.

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Research contribution

This essay gathered information from multiple research papers, compared and analyzed

different protocols, standards, tools, and software that could help achieve interoperability

between clouds. The research questions were unique to the broad literature context as they

integrated the findings from different research documents. In order to answer the research

questions and evaluate the hypothesis, the research analyzed information from multiple

sources.

The research essay could be used as a comprehensive overview of cloud interoperability

issues and could list the possible solutions to the overall problem. Additionally, the essay

could enable further research and development of new standards or could assist with the

implementation of existing ones in an effort to solve the cloud interoperability problems. The

research was performed using a meta-analysis research method.

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CHAPTER II

REVIEW OF RELATED LITERATURE

Cloud computing technology by definition should allow for the interoperability of cloud

products and services between different providers. However current cloud implementations

have proprietary solutions to monitor and access cloud resources as different approaches and

concepts do not allow the interoperability between cloud providers. Clients, organizations

and the community have realized that in order to promote interoperability, to avoid vendor

lock-in, and to ease the migration process of cloud services, standards are needed. This

section analyzed and evaluated multiple research articles related to problems with

interoperability between different cloud providers. In addition it presented protocols and

standards that help achieve cooperation between clouds.

Interoperability issues with cloud computing

Baird (2010) described cloud computing as a blend of technologies that include

virtualization, grid computing and other popular technologies commonly characterized as

Web 2.0 services. He mentioned that cloud computing is based on proprietary standards,

some open source standards and different business model implementations. Borenstein and

Blake (2011) emphasized the need for a standardization approach as multiple technologies

and a variety of standards are currently present in cloud computing. The authors mentioned

that the standards promote interoperability, enable the use of open middleware, prevent

vendor lock-in, and ease the migration of users to cloud based services. They noticed that

organizations are reluctant to move their services to cloud computing because they are

understandably cautious of becoming dependent on specific technology, or becoming locked-

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in to a particular provider. In addition, they highlighted that the success of the Internet has

made many people aware of the importance of standards in keeping the infrastructure

organized and in avoiding vendor lock-in. The authors agreed that standards are critically

important with cloud computing.

Harsh, Dudouet, Cascella, Jegou, and Morin (2012) presented a similar point of view

outlining that one major obstacle in the adoption of cloud computing is the heterogeneity of

hardware and software solutions. Customers (end users, organizations) depend on the cloud

for running their business applications and want to be able to move their data and

applications easily from one cloud provider to another. The authors stated that cloud

computing has assisted customers in their initial investment in hardware and in managing the

infrastructure, however, they acknowledge that current solutions impose the customer to use

a single cloud technology due to the high cost, or lack of ability to migrate data and the

applications, to a different cloud provider. The authors emphasized that the challenges of

vendor lock-in become even more evident in the case of Platform as a Service (PaaS) which

restrict users from the migration of their applications onto a different cloud provider.

Standardization among cloud providers is the only way to avoid vendor lock-in situation as

well as to create a more competitive market for cloud providers and customers. Harsh et

al.(2012) stressed that the situation of vendor lock-in may keep customers in fields such as

education, government, healthcare, and banking away from clouds. They agreed that

addressing the issue of interoperability and portability is necessary. Additionally, the authors

pointed out that standardization of cloud computing could enable smaller companies to enter

a cloud technology market currently dominated by the big cloud providers.

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The importance of standards in cloud computing

The importance of standards in cloud computing is described by Lewis (2013). He

mentioned that there is a lot of discussion on the role of standards in the cloud. The author

noticed that a large amount of work with standards development has already been performed

for cloud computing. Lewis observed that some parties see the cloud as something

completely new that requires an entirely new set of standards, while other groups see the

cloud as an existing technology that already has well established standards. The author

mentioned that the cloud computing community sees the lack of cloud interoperability as a

barrier to cloud computing adoption and promotion because organizations fear a “vendor

lock-in” situation. Once an organization selected a cloud provider, it is not easily to move

services or to change providers. Lewis added that a common tactic for enabling

interoperability is the use of open standards. The author concluded that there are currently

many clouds’ standardization projects. Some projects focus on standardizing parts of cloud

computing environments including workloads, authentication, and/or data access. Others

focus on standardizing how the parts should work together as a solution.

Dowell, Barreto, Michael, and Shing (2011) stated that the ability to provide

interoperability is increasingly important with the maturity of cloud computing systems.

They raised an interesting question regarding interoperability with cloud computing: “Can I

deploy existing cloud artifacts (e.g., virtual server/desktop images, software applications,

databases) on another service provider’s services without modification to those artifacts?”

The authors pointed out that the current practice of integrating software applications via an

Application Programming Interface (API) requires a significant amount of coding as well as

ongoing maintenance due to frequent modifications and updates. The authors mentioned that

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design and implementation of cloud applications using the Service-Oriented Architecture

(SOA) framework and Web Services principles enable interoperability between different

cloud providers. (Dowell et al., 2011)

Machado, Hausheer, and Stiller (2009) explained that one of the key characteristics that

makes cloud computing different from traditional enterprise systems is that the infrastructure

may be programmable. In traditional computing environments, physical resources including

servers, storage, and network connections are primarily deployed using human effort. In

cloud computing, developers can describe how the components are virtually configured and

connected and how they interact with each other. In order to accomplish this virtual

deployment and management of the resources, developers design and code multiple

Application Programming Interfaces (API). The cloud APIs are not standardized and each

cloud provider has its own specific API for deploying and managing its services. (Machado

et al., 2009) Similarly Armbrust, Joseph, Katz, and Patterson (2009) observed that the APIs

for cloud computing are still essentially proprietary and have not been standardized. As a

result, customers can not easily extract their data and programs from one cloud to run on

another. A concern of complexity of extracting or migrating data from one cloud provider to

another prevents some organizations from cloud computing adoption. (Armbrust et al., 2009)

Standards that can help solve interoperability issues

This section described popular standards that are already implemented through various

cloud providers. The standards allow solutions to interoperability challenges by designing

and implementing cloud products and services in a way that they can collaborate among

different cloud providers. Additionally, the ability to design interoperable elements enables

recycling and the reuse of the cloud components.

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Open Virtualization Format (OVF) – exists in IaaS cloud model. Zhang, Wu, and

Cheung, (2013) described the Open Virtualization Format (OVF) as a packaging standard

initiated by Distributed Management Task Force (DMTF) for the deployment of virtual

appliances. The OVF abstracts a virtual appliance as a single atomic unit enabling an error

free deployment administration of virtual appliances across multiple virtualization platforms.

The authors pointed out that this standard is widely used by major cloud providers. An OVF

package contains multiple files in a single directory. The directory always contains an XML

file called OVF descriptor with the virtual appliance name, hardware specifications and

references to other files in the package. In addition, the OVF package typically contains a

network description, a list of virtual hardware, virtual disks, certificate files and information

about the operating system. The DMTF group promotes this format as vendor neutral as it

does not contain references to any vendor specific information. The OVF is flexible and its

portable format allows packaging and the distribution of virtual appliances with the following

key features:

Efficient distribution of virtual appliances;

User friendly and automated process simplifying the installation of a virtual appliance

Support for multi virtual machine configurations

Portable VM packaging that does not rely on any particular host platform, hypervisor,

or guest operating system.

OVF helps to solve multiple cloud interoperability issues with virtual appliances including:

Life cycle of virtual appliance because standard format that includes flexible XML

descriptor enables cloud clients to automate service deployment;

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Virtualization platform interoperability as the OVF allows different virtualization

platforms to be defined within a virtual appliance;

Migration process between different cloud providers because OVF provides a simple

and unified interface for virtualization managers. (Z. Zhang et al., 2013)

Similarly, Petcu (2011) described the OVF as a widely adopted standard that can be

used across heterogeneous virtualization platforms (i.e. different hypervisor). The author

noticed that OVF format allows the clients to deploy virtual appliances with any cloud

provider. Lewis (2013) also concurred that the OVF standard enables VM migration from

one cloud provider to a different cloud provider. The author stated that a manual, time

consuming process of image retrieval from the current provider; the creation of a new image

for a new provider; and the reinstallation of software has to be performed as a result of not

having an OVF standard. (Lewis, 2013)

Harsh et al. (2012) also described the Open Virtualization Format (OVF) as a package

of virtual appliances in a standard and portable format. The authors noted that the

descriptions of virtual appliance features and components are written in an XML file. They

include:

Virtual machine’s (VM) hardware and contextualization information;

Disks and images used;

Networking;

Startup order of different VMs. (Harsh et al., 2012)

The information presented by different researchers aligned with many overlapping

comments and discussions. Researchers agreed that the OVF standard helps to achieve

virtual machine interoperability between different cloud providers. In addition, the

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documents showed that the OVF standard is implemented throughout the multiple cloud

providers.

Cloud Data Management Interface (CDMI) – exists in IaaS cloud model. Z. Zhang et al.

(2013) presented the Cloud Data Management Interface (CDMI) proposed by the Storage

Networking Industry Association (SNIA). The authors mentioned that CDMI defines the

functional interface that applications can use to create, retrieve, update and delete data

elements from a cloud. Additionally the CDMI features include:

The discovery of storage capabilities within the cloud storage

The management of storage containers and the data

The associated metadata with storage containers and objects.

The CDMI abstracts the storage as containers that hold data objects and that then enables

them to address the following cloud interoperability storage issues:

Backup

­ enabled by CDMI as a simple interface. Cloud users can schedule the backup

or perform backup operations manually using the interface.

Replication

­ made possible by CDMI containers and objects that are mapped to a mounted

file system. The mapping allows flexible replication in the low level data

storage, across different data centers.

Snapshots

­ defined by CDMI as a snapshot of a virtual machine at particular time. A

snapshot process is performed as a container update operation. The CDMI

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copy operation enables a snapshot to be restored even across different cloud

providers. (Zhang et al., 2013)

Petcu (2011) also presented CDMI as a standard for data management. The author

described CDMI as a standard that specifies a functional manner on how applications create,

retrieve, update, and delete data from the cloud. Petcu agreed that standard interfaces to

metadata and data objects are needed and that a current solution for creating, accessing,

updating and deleting data between different clouds should be CDMI. (Petcu, 2011)

Harsh et al.(2012) noted the Cloud Data Management Interface (CDMI) exists in the

IaaS cloud model and is defined as a RESTful interface. The authors agreed that CDMI

allows cloud applications and users to retrieve and perform operations on the data which

resides in the cloud. The CDMI enables the discovery of storage elements within the cloud

and allows administrators to manage containers, metadata and user accounts as well as the

permissions related to cloud storage. (Harsh et al., 2012)

In addition, Lewis (2013) described data migration from one cloud provider to another

as an important task. The author described the data migration process as being similar to a

workload migration that requires extraction of data from one cloud environment and the

upload of data to another cloud environment. The author emphasized that the program should

continue to work and to perform the same operations including: create, retrieve, update, or

delete (CRUD) on migrated data to new cloud provider as on that data in the original cloud.

The researcher was in agreement with others that CDMI is a standard that defines an API to

CRUD operations on data elements and enables discovery of cloud storage capabilities and

management of data containers. The author stated that CDMI data migration standard is

already supported by multiple providers. (Lewis, 2013) After comparing several research

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articles, it can be observed that the CDMI standard helps to achieve data migration

interoperability, thereby allowing the end user to create, retrieve, upload, or delete operations

to the data.

Open Cloud Computing Interface (OCCI) – exists in IaaS, PaaS and SaaS cloud model.

Z. Zhang et al. (2013) described Open Cloud Computing Interface (OCCI) as a boundary API

that acts as a service front-end to an IaaS provider’s internal infrastructure management

framework. The OCCI is under the umbrella of the Open Grid Forum (OGF) with industry

and academia members. The authors mentioned that OCCI was originally initiated to create a

remote management API for IaaS model-based services. This development allowed the

creation of interoperable tools for common tasks such as deployment, automatic scaling and

monitoring. Additionally, the OCCI evolved into a flexible API with a focus on

interoperability and a high degree of extensibility. The researchers noticed that the OCCI is

compatible with the existing standards such as OVF and CDMI and serves as an integration

point for standardization efforts among the Distributed Management Task Force (DMTF),

Internet Engineering Task Force (IETF) and the Storage Networking Industry Association

(SNIA). The OCCI specification defines a set of common standard management interfaces

for IaaS cloud interoperability. (Zhang et al., 2013)

Petcu (2011) emphasized that standardized tools for monitoring and managing clouds

can simplify managing the resources in multiple cloud environments. The author stated that

standard management interfaces to IaaS resources should be OCCI. (Petcu, 2011)

Additionally, Harsh et al.(2012) mentioned that Open Cloud Computing Interface

(OCCI) was initially intended to manage the deployment, automatic scaling, and monitoring

activity in the IaaS cloud model however the standard is extensible and can be used for PaaS

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and SaaS services as well. The standard supports HTTP rendering and provides infrastructure

extensions to help with cloud interoperability challenges in the IaaS model. (Harsh et al.,

2012)

Cloud Infrastructure Management Interface – Common Information Model (CIMI-CIM)

– exists in IaaS cloud model. Reddy (2013) presented CIM as a conceptual information

model that describes computing and business entities. The author mentioned that CIM

enables a consistent definition and data structure by using object oriented principals. CIM

includes expressions for common elements such as object classes, properties, methods and

associations. CIM uses terminology specific to the model and the principles of object

oriented programming. Reddy (2013) noted that the standard language used to define

elements of CIM is the Managed Object Format (MOF). CIM enables to exchange

management information about objects. And the management software that is written using

CIM standard can work without conversion among different implementations as long as the

common information model is followed. The author gave an example of an entire data center

which could be modeled because of CIM objects and different hypervisors that are able to

associate a data center using CIM entity association rules. The relationship can be easily

modeled using CIM.

Cloud Infrastructure Management Interface – Common Information Model (CIMI-CIM)

is also mentioned by Harsh et al.(2012) as a work-in-progress standardization effort within

the DMTF consortium. CIM targets the management of resources within the IaaS domain.

Additionally, the author mentioned that CIM attempts to provide support to an Open

Virtualization Format standard by using a RESTful management interface for common IaaS

components including machines, networks, volumes, etc. (Harsh et al., 2012)

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The other document published by The Open Group (2013) also mentioned that the

DMTF defined the Cloud Infrastructure Management Interface (CIMI) model, with a REST

interface and XML schema. The model uses a representation of its generic management

meta-model (CIMI-CIM). (The Open Group, 2013)

Service-Oriented Architecture and cloud computing

The Service-Oriented Architecture framework promotes creation of applications as a set

of loosely-couple components, objects that perform a specific function. This design enables

better applications integration and efficient software development by reusing of the

components, objects that are already created. Yang and Zhang (2012) described the

importance of Service-Oriented Architecture (SOA) to cloud computing. They mentioned

that the SOA framework enables services to be created that can be shared and reused. This

approach allows reusable components to be built with standardized interfaces that can be

used in multiple applications within and across different cloud computing environments. The

authors pointed out that the SOA is important to the cloud computing applications design

process as it enables group functionality among business processes and to reuse them as

interoperable services. Yang and Zhang emphasised that SOA technology simplifies the

integration of cloud computing services. They described SOA and cloud computing as

complementary technology that work together to provide enterprise, cost effective system

solutions.

Azeez et al. (2010) emphasized that Service-Oriented Architecture applications content

collection of artifacts such as data access, business logic and process, service interface, web

interface and service. The authors mentioned that SOA framework is heavily used today to

implement and connect business processes, enterprise systems with web applications. They

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agreed that the SOA framework allows the secure sharing of a single instance or artifact with

different applications using the Software as a Service model of cloud computing. The authors

described this feature as multi-tenant SOA framework where the tenant, SOA artifact,

component is isolated and reused in different applications.

Oppong and Khaddaj (2012) also agreed that the SOA framework allows the delivery of

information systems solutions based on the business requirements. They mentioned that the

SOA is a compliment to the cloud services implementation. The main features of SOA,

flexibility and interoperability, enable a better applications and services integration

throughout cloud computing models.

Cloud computing as a technology that provides flexible and scalable services on demand

to the end users is seen as an extension of SOA by Bhakti et al. (2012). The authors indicated

that the SOA framework offers reusability, efficiency and integration of services however

more work has to be performed in order to adapt the SOA framework in cloud computing

applications.

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CHAPTER III

METHODOLOGY

The objective of the methodology section in this research was to answer preliminary

research questions described in the introductory section of this essay; analyze and, categorize

cloud computing standards based on the cloud computing models, research an impact of

Service-Oriented Architecture (SOA) framework on cloud interoperability and evaluate the

hypotheses constructed in the introductory section of this research. The study was performed

using a meta-analysis research method. The first section explained the cloud computing

concept in order to understand how the cloud is designed and to provide background

information for the cloud service framework. Understanding cloud operations helped to

properly analyze the standards based on cloud computing models. The next section described

the cloud standardization initiatives and answered preliminary research questions. The

preliminary research questions were evaluated using multiple research articles. In the

following section, the standards analysis was performed based on the cloud computing

service models and functionality of each standard. The evaluation of standards was achieved

using the association analysis method in order to find the relationship between dependent and

independent variables. Establishment of association rules helped evaluate the impact of

standards on interoperability problem between clouds. The impact of SOA on cloud

interoperability was evaluated using a causal inferencing method in order to analyze the

relationship between cause and effect of SOA on the cloud interoperability. The first

hypothesis evaluation was performed using the association rule and the second hypothesis

evaluation was completed using causal effect reasoning.

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The cloud computing concept

Cloud computing, as defined by the National Institute of Standards and Technology

(NIST), is “a model for enabling convenient, on-demand network access to a shared pool of

configurable computing resources (e.g., networks, servers, storage, applications, and

services) that can be rapidly provisioned and released with minimal management effort or

service provider interaction”.

Cloud computing promotes five essential characteristics:

On-demand Self-service which provides clients with services when needed, without

human intervention.

Broad Network Access which allows users to access services using a broad range of

network devices, such as browsers, mobile phones, tablets, laptops, and workstations.

Resource Pooling which enables resources to not be dedicated to any particular

consumer but which are shared and allocated as required.

Rapid Elasticity which allows the amount of resources for a consumer to be expanded

and contracted easily and quickly in order to meet demand.

Measured Service which determines the amount of resources consumed in order to

provide automatic expansion and contraction and which provides usage visibility to

providers and consumers. (The Open Group, 2013)

Based on the services that it provides, there are three types of cloud service models:

Infrastructure-as-a-Service (IaaS) which consists mainly of computational

infrastructure available over the internet, such as computing power, data storage,

networking,

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Platform-as-a-Service (PaaS) which is based on application development platforms

and enables the use of libraries, tools, and services in order to create and host

applications, and

Software-as-a-Service (SaaS) which enables cloud providers to offer applications to

clients for use as a service on demand. (Lewis, 2013)

The cloud computing architecture shown in fig. 1 includes the above mentioned service

models: software, platform and infrastructure within the context of information systems.

Fig. 1. Cloud computing architecture.

Software is a program that performs logical functions and processes data based on

predefined requirements. Platform is an environment that supports the applications and

performs generic functions. Infrastructure is a collection of physical components such as

processing power, data storage, or network communication resources. The software, platform

and infrastructure models can be seen in the cloud resource allocation as software application

programs (SaaS model), software application platforms (PaaS model) and virtual processors

and data storage (IaaS model). Fig. 2 shows the concept of cloud resource allocation.

22

Fig. 2. Cloud computing resource allocation.

(The Open Group, 2013)

The interoperability and portability of the IaaS service model benefits the most from

standardization efforts. The IaaS components are mainly virtual machine images and storage

units of data. The standardized format of virtual machines and data collation allow users to

migrate an image from one provider to another and run it without performing any changes.

Platform as a Service provides many capabilities right “out of the box,” including managed

application environments, user authentication, data storage, and other functionality in the

form of libraries that can be integrated into applications. The functionalities are tied to a

specific programming language and runtime environment. For example, the Google App

Engine supports applications written in Java, Python and Go. Microsoft Azure supports

applications written in .NET, and more recently applications written in Java, PHP, and

Node.js. The PaaS adoption allows for rapid development and deployment of the

23

applications. The PaaS model enables providers to make applications more portable and

interoperable by selecting platforms that support standardized tools and languages including

Java language, Java Database Connectivity (JDBC), Open Database Connectivity (ODBC),

and Structural Query Language (SQL).

The SaaS model is different than IaaS and PaaS as it relates to a licensing agreement

with third party software. The standardization of SaaS is limited as compared to the IaaS and

the PaaS model. The SaaS model can benefit from standardization of data structure within

applications to enable easy migration of data to a new SaaS provider. (Lewis, 2013)

Cloud standardization initiatives

In the introductory section of this essay there were preliminary questions that were

created in order to better understand the research problem. The first question asked was

“What are the interoperability problems with cloud computing?” Based on the review and

analysis of multiple research documents, the conclusion was that interoperability issues

between clouds consist of:

Vendor lock-in when certain SaaS applications are built to specific, proprietary

platform or infrastructure. (Miranda, Murillo, Guillén, and Canal, 2012; Petcu, 2011;

Lewis, 2013; Raines, 2009; Parameswaran and Chaddha, 2009)

Lack of portability of VMs in order to allow migration VMs between clouds. (Petcu,

2011; Harsh et al., 2012; Loutas, Kamateri, Bosi, and Tarabanis, 2011)

Proprietary cloud API makes integration of cloud services with existing legacy

systems difficult. (Dillon, Wu, and Chang, 2010; Lewis, 2013; Parameswaran and

Chaddha, 2009)

24

Security, privacy and trust are important subjects to ensure that different cloud

providers provide the same level of security. (Dowell et al., 2011; Borenstein and

Blake, 2011; Machado, Hausheer, and Stiller, 2009)

Cloud interoperability standards are developed by members of many not for profit

organizations as well as academia, government and cloud providers.

The second preliminary question in the introductory section asked: “What standards can

be implemented in cloud computing in order to help solve the issues of interoperability.”

Table I summarizes the organizations’ and groups’ involvement in standards creation. The

table contains standards that are evaluated within this essay.

Table I. Summary of groups involved in standard cloud creation.

Organization Standard Name Purpose

Distributed

Management Task

Force (DMTF)

Open

Virtualization

Format (OVF)

Packaging format that is independent to

virtualization platform or hypervisor. It allows

migrating virtual appliances between different

cloud providers’ environments. The standard

optimizes deployment of virtual appliances and

enables portable virtual machine packaging.

Cloud

Infrastructure

Management

Interface –

Common

Information

Enables the definition of entities and data

structure by using object oriented principals.

This model enables the exchange of

management information and targets the

management of resources through IaaS. CIM

attempts to provide support to the Open

25

Model (CIMI-

CIM)

Virtualization Format standard by using a

RESTful management interface for common

IaaS components such as virtual machines,

networks and data stores.

Open Grid Forum

(OGF)

Open Cloud

Computing

Interface (OCCI)

Describes standard management interfaces

within the IaaS cloud service model. It is used to

develop interoperable tools for common tasks

such as monitoring, deployment and scaling.

The specification is compatible with OVF and

CDMI and is extensible to the PaaS and SaaS

service models.

Storage

Networking

Industry

Association

(SNIA)

Cloud Data

Management

Interface (CDMI)

Defines the application interface which creates,

retrieves, updates and deletes data element

operations. It is used to abstract the storage

containers and to allow the data management as

well as the migration process to upload data to

another cloud environment.

26

Cloud standards analysis

Once interoperability problems with cloud computing were identified and understood,

the standards initiatives were then introduced and described. The next preliminary question

asked if the standards could be implemented and could help with interoperability challenges

in all cloud computing service models. In order to answer this question the association

analysis method was used in an effort to find a relationship between dependent variables

(migration of virtual machines, data migration, and workload management) and independent

variables (virtual machine format, migration protocols, management framework). The

establishment of association rules proved useful to evaluate the impact standards had on the

problem of interoperability with the cloud. The proposed standards would help to achieve

interoperability within certain cloud computing service models.

Infrastructure as a Service model – interoperability issues. The IaaS model benefits the

most from standardization initiatives. The reason is that composition of IaaS model includes

workloads that are represented by virtual machines, storage data units as well as networks.

The virtual machine (VM) migration process (dependent variable) is associated with

standard efforts such as Open Virtualization Format (independent variable) that

enables the extract of an image from one provider and to then be able to upload it to

another without a manual process of reinstalling the virtual machine or setting up of

services and programs from the start. (Lewis, 2013)

In order to enable the process of live migration of virtual machines, the issues with

virtualization platform and virtualization manager have to be taken into consideration.

There are different virtualization platform technologies e.g. host operating system,

host architecture as well as hardware-assisted virtualization compatibility e.g. Intel

27

Virtualization Technology versus AMD Virtualization. A virtualization manager that

manages VMs on physical hosts should be able to access and migrate VMs between

different cloud providers. (Z. Zhang et al., 2013)

The data migration process (dependent variable) is associated with a standard such as

Cloud Data Management Interface (CDMI) that enables the users to extract data from

one provider and then to upload it to a different cloud provider. Fig. 3 shows the

cloud storage reference model using Cloud Data Management Interface.

Fig. 3. The cloud storage reference model using CDMI.

(SNIA, 2012)

28

CDMI defines an API to create, retrieve, update, and delete (CRUD) data operations

from the cloud data storage environment. The Representational State Transfer

(REST) interface is considered as architecture and not as protocol. The REST

implementation identifies entities and addresses them via a Universal Resource

Identifier and provides interface as defined in HTTP such as GET, POST, PUT, and

DELETE. The RESTful interface is defined in the CDMI implementation. This

standard is useful for raw data when the cloud resource is used as a container. (Lewis,

2013) The Open Cloud Computing Interface (OCCI) standard also provides support

for storage management. It is compatible with CDMI standards. The OCCI helps with

backup and snapshot operations. The OCCI and CDMI have common RESTful

orientation and both use HTTP as a communication protocol or query service

discovery. (Teckelmann, Reich, and Sulistio, 2011)

Fig. 4 presents the OCCI boundary protocol in the cloud providers’ architecture.

Fig. 4. The OCCI boundary protocol in cloud provider’s architecture.

(Nyren, Edmonds, Papaspyrou, & Metsch, 2011)

29

The service consumer can be the end user and/or other information system. The OCCI

can manage API for all kinds of resources and can provide high level of

interoperability. (Nyren et al., 2011)

The network contains two important topics related to network interoperability

including addressing network and communication application levels between

different cloud providers. The main issue is to have a reliable remote access to

applications even when they move between different subnets. An application level

communication should be designed as a RESTful Application Programming Interface

(API) in order to minimize coupling of the client and server components. The two

major communication protocols that implemented RESTful APIs are HTTP as an

application transport protocol and XMPP which is XML over TCP. (Z. Zhang et al.,

2013)

Table II presents a summary of functionality of the OVF, OCCI, CDMI standards

related to virtual appliance support, storage operation, network use and security subjects such

as authentication, authorization, accounting and encryption.

Table II. Summary of functionalities of OVF, OCCI, CDMI standards.

OVF OCCI CDMI

Virtual appliance

Virtualization manager n/a

Storage backup

Storage replication

Storage snapshots

Network communication n/a

30

Security authentication n/a

Security authorization n/a

Security accounting n/a

Security encryption n/a

- provide functionality; - do not provide functionality

(Teckelmann et al., 2011)

Platform as a Service model – interoperability challenges. The PaaS model provides

“out of the box” functionality including management of user authentication, application

environments and application communications in the form of libraries that are fully

integrated. These capabilities are related to a particular programming language and runtime

environment made available by the cloud provider. The main benefit of the PaaS model is a

rapid application deployment. However vendor lock-in is a major drawback because of a lack

of standardized tools and of selected programming languages available by different cloud

providers. The first steps to enable interoperability within platform as a service model would

be to have the cloud providers standardize the tools; to support the same programming

languages such as Java, Python, PHP or .NET; and, to allow data access interfaces including

Java Database Connectivity (JDBC), Open Database Connectivity (ODBC). The cloud

providers might agree and support the same programming language however the biggest

issues with the interfaces. They might be incompatible with other cloud providers with

specific services such as authentication, data structure, queues and hash tables. Additionally,

the proprietary option may be more powerful and deliver greater benefits over the

standardized features. For example, the default data store of Google App Engine offers

automatic replication of data across data centers. Clients are able to access the data stores

31

using standardized API or low level proprietary API. The standard API allows better

interoperability and portability of the applications between cloud providers however it does

not offer specific control features as does the low level proprietary API. (Lewis, 2013)

Standardization groups are in agreement that it is important for the development of a

common framework enabling different cloud platforms to interoperate. In order to succeed,

two standardization approaches have been proposed: A standardized cloud interface to unite

multiple cloud APIs and a common cloud data model. In addition, multiple researchers agree

that a common management model has to be developed to consistently manage PaaS entities

between different cloud providers. The proposed direction should eliminate the current

vendor lock-in issue and should enable interoperability between different cloud

environments. (Loutas, Kamateri, and Tarabanis, 2011)

Software as a Service model – interoperability problems. The SaaS model provides a

complete software package with email, customer relationship management (CRM), enterprise

resource planning (ERP) and/or accounting instead of an application deployment

environment. The SaaS standardization process is limited as each cloud provider offers

different software or their own processing logic. The integration process in the SaaS model is

possible with the standardization of the data structure and data storage of those applications.

The standardized APIs can help extracting or sharing data among multiple cloud providers.

(Lewis, 2013)

Data portability is an important part of the cloud interoperability process. The ability to

use data components across different applications or cloud providers is a key enabler to the

clouds interoperation. Interoperability challenges in SaaS model exist not only between

different software components implementation but also between identical software

32

deployments in different clouds. The data synchronization process is critical in order to

ensure that an application works in different cloud’s environments. Usually copies of the

same data must be maintained in a consistent state. The high latency communication links

between clouds create a challenge in synchronizing data in a timely manner. In order to

enable the interoperability of applications between the clouds, the communication protocols,

the discovery of components and services, the data management systems and the

management of the common processes have to be implemented and standardized. The

application design framework such as Service-Oriented Architecture (SOA) can improve

application interoperability. (The Open Group, 2013)

Service-Oriented Architecture and cloud computing analysis

The evaluation of Service-Oriented Architecture (SOA) was performed using multiple

research studies. The causal inferencing method was used to analyze the relationship between

cause and effect of SOA on the cloud interoperability.

The SOA framework provides functionality to interconnect the application services with

other applications through standard interfaces and messaging protocols. Service-Oriented

Architecture offers a software development approach that is task specific, reusable and

service oriented. The SOA framework enables functional business components such as the

credit card validation process in order to gain better reusability, flexibility and manageability.

(Mirzaei, 2008)

SOA and cloud computing are different concepts however they complement and support

one another. SOA is an architectural framework that guides business solutions to create

reusable software components as cloud computing provides information systems as a

33

services in order to enable organizations to build their SOA business solutions. (Tsai, Sun,

and Balasooriya, 2010)

The primary features and benefits of using SOA include:

Interoperability of SOA services such as service requester, service provider and

service registry that communicate with each other using synchronous or asynchronous

communication mechanism.

Independent service function that enables grouping of the components in self

contained modules.

Loosely coupled design of services that allow binding of services without knowledge

of the technology.

Transparent location of services that are designed to reflect business processes instead

of location of the services to the clients.

Multiple researchers agree that the SOA framework provides reusable solutions that can be

implemented to help with cloud integration and cooperation challenges. The SOA and cloud

computing complement each other in that the SaaS cloud model provides a service based on

the SOA business framework design. The Service-Oriented Architecture framework is a

blueprint of enterprise information technology architecture whereas cloud computing is a

supplier of the architecture, services to the clients. Cloud computing and SOA allow the

creation and delivery of services to the end users that are robust, cost effective and

performance oriented. (Yang and Zhang, 2012)

Fig. 5 shows conceptual building blocks of the SOA solution and how they relate to

each other.

34

Fig. 5. The SOA Reference Architecture.

(The Open Group, 2013)

Integration of Service-Oriented Architecture with the SaaS model of cloud computing

allows designing software components that are reusable and flexible. In order to integrate

cloud computing services using SOA some of the principals should be followed:

Fine-grained services that can improve the reusability as well as flexibility of

configuration to support business needs.

Location independence of services that enables rapid discovery of the services

whenever the service is needed.

Independent communication of services which allows software components to

exchange information regardless of communication interface or protocol.

35

Independent security of services enabling trust between different components in the

federated security system.

Loosely coupled of the architecture that allows migration of one software instance to

another without affecting the other components. (Yang and Zhang, 2012)

The hypotheses evaluation

The first hypothesis:

After analyzing the association of the OVF standard with the portability of virtual

machines or virtual appliances, the research showed that the implementation of the OVF

format by cloud providers enabled virtual machine portability. The OVF format is vendor

neutral and allows an efficient and flexible packaging. The researchers agreed that OVF

addresses multiple issues of interoperability of virtual machines in cloud computing such as

life cycle, virtualization platform and management.

This research posed and validated a working hypothesis “If Open Virtualization Format helps

achieve portability of the virtual machine then implementation of OVF would solve the

problem of virtual machine migration from one cloud provider to another.”

The study described OVF standard using different sources of information. Multiple research

papers reported similar findings. It is evident that OVF helps to achieve portability of virtual

machines. The hypothesis is proving to be true as major cloud providers have implemented

the OVF standard and users are now able to migrate VMs from one cloud provider to

another.

The second hypothesis:

The process of causal inferencing was used to analyze the effect of the implementation

of the SOA framework on interoperability in the SaaS cloud computing model. The causal

36

effect reasoning indicated that SOA and cloud computing compliment each other and help to

achieve interoperability. However, the research did not conclude the hypothesis “If Service-

Oriented Architecture helps to solve the problem of software as a service interoperability,

then the use of SOA would resolve interoperability problems within SaaS model of cloud

computing” is true as many variables had to be taken into consideration before the SOA

framework could allow for software application interoperability between different clouds.

The main challenges in order to be able to achieve interoperability with clouds using the

SOA framework include:

A guarantee high availability of cloud services,

A rapid and seamless deployment of applications within clouds,

An effective finding of different cloud services, and

A secure isolation security of application components with cloud. (Yang and Zhang,

2012)

37

CHAPTER IV

ISSUES, CHALLENGES AND TRENDS

The biggest problem with addressing cloud interoperability is that there are too many

proposed standards to address the same problems. In order to standardize functions of cloud

computing such as workload, data migration, virtual machine portability, storage, replication,

backup, and snapshot interoperability discussions between cloud providers, user and

standardization working groups have to take place and the initiatives need to be more

responsive.

Issues and challenges with the cloud interoperability

In order to achieve interoperability between different cloud systems, implementation

and support of their standards is required. Although standards can help to attain

interoperability there are some issues in that providers are sometimes reluctant to come to an

agreement on these standards. Some rationale for this lack of interest includes:

a lack of support by cloud providers to not adopt certain standards for their own

commercial gain;

a requirement is needed to identify specific standards requires expertise and

experience in the subject matter;

a need exists for a level of agreement among cloud providers, hardware and

software vendors for the implementation of standards. (The Open Group, 2013)

Cloud providers set up their own proprietary implementation on how the applications, APIs,

data stores, and management interfaces communicate. This situation creates vendor lock-in

and makes the integration of cloud services very difficult. Although various organizations

38

believe that this issue is becoming increasingly more important and that there is a general

feeling that standardization will address interoperability issues, the major cloud providers are

still not treating the lack of interoperability as a high priority. The cloud standardization and

interoperability process will not progress without consensus from the key cloud vendors.

(Dowell et al., 2011)

The challenges of vendor lock-in and other cloud computing interoperability issues are

more complex and more difficult to solve in higher cloud models such as PaaS and SaaS as

seen in fig. 6.

Fig. 6. Increasing interoperability issues in cloud models.

(Z. Zhang et al., 2013)

Providers and industry experts are looking to solve issues within each cloud model at the

same time. However they need to begin by first solving it through the IaaS model as it will

assist cloud platforms to then coexist. Once solved through the IaaS model, they can begin

moving to the higher, more complex levels. The challenge however in IaaS standardization

starts with different hardware and software virtualization solutions. The physical host servers

have different type of processors, hardware accelerators, scheduling mechanisms and

39

resource allocation that might lead to the poor performance. Additionally, data that is

distributed across various locations should be managed efficiently to ensure consistency and

integrity. Also, network latency and data access time is an issue. Cloud providers invented

their own proprietary data management tools and are reluctant to host data in any

environment that they do not control. This illustrates another challenge of trust and security

between different cloud providers.

There are also challenges within the PaaS model including that end users are not always able

to migrate an application deployment because of incompatible Application Programming

Interfaces (APIs) between cloud providers. (Harsh et al., 2012)

Software portability in the cloud versus traditional computing system

In traditional computing systems the interoperability and portability of the applications

is achieved by use of same programming language, source code and a compiler. For example

in the UNIX operating system the programs are written in C programming language. In order

to deploy the applications on different system the recompiling process is necessary. The

operating system serves as a layer that hides physical or virtual hardware from the

application. Lower level programming languages such as C are operating system dependent

however higher level programming language such as Java provides virtual machine, runtime

environment that also hides the operating system from the application. Because the

applications are written in supported programming language and compiled by the same

standard operating system environment, the migration process in traditional computing is

even possible among different hardware systems as shown in fig. 7. (The Open Group, 2013)

40

Fig. 7. Portability of applications in traditional computing system.

(The Open Group, 2013)

The process described and shown above is similar to the cloud computing platform as a

service (PaaS) portability. The applications that run in a cloud computing environment have

similar interoperability challenges as in the traditional system. They include: hardware,

virtualization layer (IaaS interoperability issues), operating system, programming languages

and software libraries (PaaS interoperability issues). In the traditional computing systems as

with cloud computing, the programming language and software libraries are a key to

application portability. Currently, there are two standard libraries that enable application

portability such as Java 2 Platform Enterprise edition (J2EE) and the .NET framework. Java

platform provides server functionality including:

Data storage and retrieval

Data management

Process scheduling

41

Platform to platform communication using Simple Object Access Protocol (SOAP) or

raw Hypertext Transfer Protocol (HTTP).

The .NET software framework runs on a Microsoft Windows operating system and supports

platform functionality similar to J2EE.

The challenges of portability of applications between different clouds platforms (PaaS) reside

similarly as in the traditional systems with software libraries and programming languages.

The clouds providers often implement their own proprietary software libraries and

programming language. The applications that are designed using proprietary technology will

not be able to migrate easily between different clouds. (The Open Group, 2013)

Trends of migration of e-learning platforms into cloud computing

Distance education is an increasingly more popular form of education. E-learning

platforms are constantly improving in effort to deliver the best educational experience as well

as to keep up with the always changing field of information technology. The new direction of

delivering the distance education content is to host e-learning systems in a cloud

environment. Web 2.0 and cloud computing have changed the traditional model for

publishing material into a more collaborative model whereby web applications are reused and

therefore enable social interaction. The benefits of using Web 2.0 technology when

developing e-learning application include:

places the learner at the center of online activities,

allows a user to personalize their learning environment,

enables the learner to create and share content with others, and

provides a more flexible and cost effective e-learning system. (Ouf, Nasr, and

Helmy, 2011)

42

In general, e-learning consists of a course management system (CMS) and an

assessment management system (ASM). E-learning systems are usually based on

client/server architecture and web technology. This particular architecture has some

limitations including a lack of flexibility, scalability and interoperability. An issue arises in

that the learning resource cannot be shared and easily delivered onto different platforms such

as mobile devices, etc. Currently, mobile devices have limited processing power, memory

and screen sizes when compared to desktop computers. And, traditional database servers do

not perform well with the constant growth of databases and the increased load as numerous

users simultaneously access the system. Cloud computing allows data processing to be

performed on the server side and provides a dynamic resource allocation when needed.

(Phankokkruad, 2012)

Cloud computing provides services from which distance education learning objects and

learning processes can benefit. The cloud computing environment and SOA framework are

two key technologies that play an important role in building scalable and reusable

educational learning objects. The idea of reusing existing learning objects allows for new

learning materials, courses to be created efficiently and effectively. (Kalagiakos and

Karampelas, 2011)

Cloud computing enables new opportunities to enhance the process of distance

education. Some potential benefits of cloud computing for the field of education include:

ability for students to work from anywhere and on any device with Internet access,

ability to provide a scalable infrastructure that provides on-demand resource

allocation,

enablement of a large amount of processing power,

43

option to lower costs for academic institutions.

Cloud computing is an environment that provides for and manages applications and data. The

integration of Web 2.0 technology, with cloud computing and SOA framework satisfy the

educational institution requirements for a distance education platform. Cloud computing is

considered as a scalable, flexible environment to host e-learning applications. (Ouf et al.,

2011)

44

CHAPTER V

CONCLUSIONS AND RECOMMENDATIONS

The essay describes interoperability challenges between different cloud providers. The

research analyzes and evaluates multiple standards including OVF, CDMI, OCCI, CIMI-

CIM and the SOA framework that may influence cooperation among different cloud

platforms. The standards are evaluated based on the cloud computing service models. At the

beginning, the study answers some preliminary research questions in order to help

understand the interoperability problems with cloud computing. The examination of various

research articles indicated that cloud interoperability problem impact end users in a way of

vendor lock-in, lack of portability of virtual machines between clouds, difficult integration of

cloud services and no standardized security level. Subsequently, the research analyzes the

effect of Service-Oriented Architecture (SOA) on the interoperability in the cloud computing.

Multiple researches agreed that SOA framework enables applications, services to be shared

and reused across different cloud environments.

Conclusions

The research constructs and evaluates two hypotheses. The first hypothesis “If an Open

Virtualization Format helps to achieve the virtual machine portability then the

implementation of OVF would solve the problem of the virtual machine migration from one

cloud provider to another” is evaluated using association analysis. The association,

relationship analysis between dependent variable (migration of virtual machines) and

independent variables (Open Virtualization Format) indicated that OVF helps achieve

portability of the virtual machines. The hypothesis is tested to be true and major cloud

45

providers currently support the OVF standard format. The second hypothesis “If a Service-

Oriented Architecture helps to solve the problem of software as a service interoperability,

then the use of SOA would resolve the interoperability problems with the SaaS model of

cloud computing” was formulated and evaluated using causal inferencing. Analyzing cause

and effect reasoning of implementation of SOA framework in cloud computing indicated that

SOA helps achieve interoperability. However the research did not definitely conclude that

SOA solves the interoperability problem in the SaaS model as many other variables have to

be taken into consideration.

The research is performed using the meta-analysis method. The various questions

related to interoperability problems within clouds are answered using different research

materials, articles and studies to ensure the information is aligned. The research evaluated the

most popular cloud computing standards including OVF, CDMI, OCCI and CIMI-CIM as

well as verified the idea that the SOA framework can help to accomplish interoperability in

clouds. Different research articles are used to reinforce the authenticity and the validation of

different standards responsible for cloud interoperability. The research shows that agreement

and implementation of the same standards in different cloud environments solves particular

interoperability problems. The study highlights that implementation of the standards help

resolve interoperability challenges between different cloud providers. The research essay can

be used as an overview of the cloud interoperability problems and list possible solutions and

can enable further research and development of the new standards.

46

Recommendations for further research

In order to advance with further research, a simulation should be performed to

determine which standard, application, tool or protocol is the most suitable to minimize

interoperability problems between different cloud environments. For example, simulation

analysis of data migration between different cloud providers using various standards and

migration methods can be tested, analyzed and evaluated. Then the results can be observed,

reviewed and, as a consequence, proper recommendations can be made. Simulation software

can be designed and used to predict behavior and interaction of multiple interoperability

components among clouds such as data migration, workload management or monitoring

tools. Additionally, the survey can be performed in order to gather information from users to

evaluate the proposed interoperability solutions. Finally, conducting interviews with a subset

of participants who responded to the survey would be beneficial. The purpose of the

interview would allow additional questions to be asked in order to enhance knowledge of

client requirements related to cloud interoperability.

The research describes the interoperability challenges between cloud providers and

emphasizes that a standardized approach is necessary in order to allow end users to freely

choose and distribute cloud products and services from one cloud to another. Reaching

industry consensus is not a simple task as cloud providers invent their own proprietary data

management tools, incompatible APIs that are not supported between different cloud

providers. The research describes cloud interoperability challenges and presents possible

standards that can enable the cloud cooperation process. The study intends to initiate further

research and development of the new standards, tools and protocols that can solve and enable

interoperability between different cloud providers.

47

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