=Paper=
{{Paper
|id=None
|storemode=property
|title=Cloud Computing Interoperability Approaches - Possibilities and Challenges
|pdfUrl=https://ceur-ws.org/Vol-920/p30-kostoska.pdf
|volume=Vol-920
|dblpUrl=https://dblp.org/rec/conf/bci/KostoskaGRK12
}}
==Cloud Computing Interoperability Approaches - Possibilities and Challenges==
https://ceur-ws.org/Vol-920/p30-kostoska.pdf
Cloud Computing Interoperability Approaches –
Possibilities and Challenges
Magdalena Kostoska Marjan Gusev
Ss. Cyril and Methodius University Ss. Cyril and Methodius University
Faculty of Information Sciences and Computer Faculty of Information Sciences and Computer
Engineering Engineering
16 Rugjer Boshkovikj 16 Rugjer Boshkovikj
Skopje, FYR Macedonia Skopje, FYR Macedonia
magdalena.kostoska@finki.ukim.mk marjan.gushev@finki.ukim.mk
Sasko Ristov Kiril Kiroski
Ss. Cyril and Methodius University Ss. Cyril and Methodius University
Faculty of Information Sciences and Computer Faculty of Information Sciences and Computer
Engineering Engineering
16 Rugjer Boshkovikj 16 Rugjer Boshkovikj
Skopje, FYR Macedonia Skopje, FYR Macedonia
sashko.ristov@finki.ukim.mk kiril.kjiroski@finki.ukim.mk
ABSTRACT applications running in different clouds to share data, appli-
The Cloud Computing Interoperability (CCI) is a hot re- cation to be transferred to another cloud solution or having
search topic and has been addressed by many scientists, same functionalities and options in different cloud platforms
architects, groups etc. A lot of different approaches and or solutions. Also data and images portability, management
possible solutions are published, but there is no accepted and migration among different cloud solutions are not ex-
standard or model yet. This paper is a survey of the most cluded. The interoperability may be defined on every level
influential published CCI models and discusses their pos- of the cloud computing service stack: Infrastructure as a
sibilities and challenges. The accent in this paper is set to Service (IaaS), Platform as a Service (PaaS) and Software
analysis of the Software as a Service (SaaS) CCI model based as a Service (SaaS).
on adapters. In this paper we will use the definition given by Enterprise
The current state of the cloud computing market and the Interoperability Science Base (EISB) Glossary [2].
results of recent Cloud Computing (CC) market surveys are
also included in our analysis. Definition 1 (Cloud Computing Interoperability).
The presented conclusion addresses the increasing trend in Cloud interoperability is the ability of cloud services to be
the usage of cloud computing and the lack of visible result able to work together with both different cloud services and
to achieve cloud computing interoperability. So the next providers, and other applications or platforms that are not
logical step is to create adapters to achieve interoperability cloud dependant. [2]
at the SaaS level.
[14] is one of the first papers that suggests the need for
cloud computing ad CCI and describes possible scenarios for
Categories and Subject Descriptors CCI. As cloud computing became more widely used technol-
D.2.0 [Software Engineering]: General—Standards; D.2.11 ogy, the CCI has been analyzed by more research communi-
[Software Engineering]: Software Architectures; D.2.12 ties. Yet, there is no unique solution on the horizon.
[Software Engineering]: Interoperability In this paper we will represent and analyze some of the
suggested models for interoperability, analyze the current
state of the market and forecast future direction for devel-
Keywords opments.
Cloud computing, interoperability, comparison Section 2 presents the results from CC surveys and gives
overview of the current state of the CC markets and cus-
tomers opinions. Section 3 presents published CCI models
1. INTRODUCTION and their current progress and also describes new CCI ap-
There are different perceptions of the term Cloud Com- proach. Section 4 evaluates the presented models.
puting Interoperability (CCI) defined by different points of
views [13] [10] [15]. This term may be referred as ability of
2. CURRENT STATE OF CLOUD COMPUT-
BCI’12, September 16–20, 2012, Novi Sad, Serbia. ING MARKET
Copyright c 2012 by the paper’s authors. Copying permitted only for private and
There are a lot of surveys of the current state of the cloud
academic purposes. This volume is published and copyrighted by its editors.
Local Proceedings also appeared in ISBN 978-86-7031-200-5, Faculty of Sciences,
computing market. According to the Business Web Host-
University of Novi Sad. ing survey for small and midsized businesses [11] and the
30
Figure 1: Results for cloud computing concerns [11].
Figure 4: Cloud orchestration [14].
3.1 Unified Cloud Interface/Cloud Broker
The Unified Cloud Interface Project have goal to create
an open and standardized cloud interface for different cloud
api’s [1]. This model of unified cloud interface (cloud bro-
ker) is discussed in [14]. The idea is ”to come up with an
abstraction layer that is agnostic to any cloud API, plat-
form or infrastructure”. The unified cloud interface (UCI)
should create API for other CC APIs, to serve as common
interface, to provide specification and schema for integration
with other management models and exchange management
information and address Infrastructure as a Service (IaaS)
and Platform as a Service (PaaS). This model suggests the
usage of semantic web and OWL. The overview of the UCI
Figure 2: Results for inhibition to adopt CC [4]. is shown in Figure 3.
This approach is proposed by a non-profit organization
Cloud Computing Interoperability Forum (CCIF). Unfortu-
inaugural North Bridge, GigaOM Pro and 451 Group 2011 nately some of the biggest companies in CC have rejected
Future of Cloud Computing Survey [4] one of the biggest the CCIF approach, so it is unlikely that this model will be
concerns the prevents customers of adopting CC are secu- widely used.
rity and interoperability.
500 customers were analyzed in the Business Web Hosting 3.2 Enterprise Cloud Orchestration Platform
survey [11]. The inaugural North Bridge, GigaOM Pro and / Orchestration Layer
451 Group have provided a survey on 2011 Future of Cloud
The solution InterCloud presents a federation of clouds
Computing [4] by analyzing 417 participants (46% CC ven-
[14]. The source of the idea is to present Internet as a net-
dors and 54% non-CC vendors). The results of both of the
work of networks. In this model different cloud providers can
surveys about CC concerns are shown in Figures 1 and 2.
register their cloud services within the orchestration layer
As we can see the results are quite similar: security rep-
(OL) similar to publishing the web services with the Uni-
resents 20% of the answers and interoperability 13%.
versal Description, Discovery and Integration (UDDI) [5].
Also both surveys predict increase of the usage of CC and
[14] suggest ”The orchestration layer can then dynamically
show high usage of SaaS and IaaS.
select and bind to services based on criteria/algorithms that
The lack of interoperability was introduced by companies
determine the best cloud service for a particular job based on
when they started to develop adapters in order to achieve
factors like highest performance, lowest cost or other require-
transfer of real applications to the cloud. Companies like
ment as specified by the client”. An example of invocation
CloudSwitch and RightScale already made the first step;
of three different services provided by different CC provider
they have developed tools to enable moving applications to
is shown in Figure 4.
target clouds.
Beside the standard CC security issue, this model has a
lot of considerations to be solved: limitation of the required
3. OVERVIEW OF CCI MODELS service platform support, dealing with delays and latencies
Diferrent models have targeted different layers od the CC due to the OL performance overhead and the data volumes
stack: [1] addreses all the layers of the cloud, while [5], [3] transportation overhead.
and [6] target only the IaaS layer. In the following section Unfortunately this model is also not accepted by the most
we will describe these models. influential CC providers.
31
Figure 3: UCI architecture [1].
3.3 Blueprint for the Intercloud
[3] discusses use cases for CCI including interoperability,
inter-cloud protocols and formats for enabling the use cases.
Two types of use cases are described: use cases involving
a physical metaphor and use cases involving an abstract
metaphor. The physical metaphor includes servers, disks,
network segments, etc, and the abstract metaphor includes
blob storage functions, message queue, email functions, mul-
ticast functions, etc.
The first type of use cases is about virtual machines (VM)
instantiation and mobility. They include VM mobility trans-
actions, reliable conversations between the clouds, VM trans-
port and VM instantiation formats.
The second type of use cases is about storage interoper-
ability and federation. It includes storage subcontracting of
one cloud provider with another and assumes reliable con-
versation and reliable transport among clouds [3].
[3] suggests clouds of two kinds, one using hypervisors
from VMware and another using open source hypervisors
such as Xen and KVM from RedHat. ”Intercloud Protocols”
are tested on these clouds. Figure 5 shows the architecture of
Intercloud standards. A set of already established protocols
are subject for further research and extension.
This research only shows directions for further standard-
ization and it is only a starting point. It requires a lot of
future work and communication among existing CC vendors.
Figure 5: Architecture for intercloud standards [3].
32
Figure 7: Types of interoperability between appli-
cations in the cloud [12].
• Interoperation among applications inside a single cloud,
• Applications to exchange information and trigger op-
Figure 6: Cloud service reference architecture [7]. erations across different cloud environments,
• Software programs to connect multiple cloud environ-
ments and to integrate data and applications across
3.4 Management Interoperability for Cloud
clouds in a unified manner and
Systems
In 2009 the Distributed Task Management Force (DMTF) • Migration of a cloud application from one cloud envi-
has formed a group dedicated to address the need for open ronment to another.
management standards for cloud computing. This group
is called ”Open Cloud Standards Incubator” and their aim There are no visible results in this area so far.
is to develop a set of informational specifications for cloud
resource management [6]. Their target is the IaaS interop-
3.6 Adapters
erability. The software adapters have existed for a long time. They
This group is promising since the biggest CC vendors like provide service and communication between incompatible
AMD, Cisco, Citrix, EMC, HP, IBM, Intel, Microsoft, Nov- software and services; and by definition they provide inter-
ell, Red Hat, Savvis, Sun Microsystems, and VMware are operability. The overall goal is the data exchange.
part of this group. In the case of cloud computing adapters can provide a
From 2009 till 2010 this group has created white papers new possible solution to the currently nonexistent SaaS stan-
about their vision for interoperable clouds [7], architecture dards. The pool of SaaS CSP providers is growing up every
for managing clouds [8] and use cases and interactions for day and there are too many software types that can be found
managing clouds [9]. Since then they are working on Cloud in the cloud. It is impossible to create adapters for each type
Infrastructure Management Interface (CIMI) Model and the of software. Therefore there are two possible approaches:
work is still in progress.
• Developing adapters for general world-wide used types
This group has isolated the cloud management challenges,
of software like CRM, ERP etc...
created scenarios for interaction using interoperable cloud
standards, defined cloud service lifecycle and created Cloud • Developing custom adapters for specific software.
Service Reference Architecture [7]. Figure 6 shows the pro-
posed reference architecture. Our target group is the first one. Most of the general ap-
In [8] they have created more detailed definition of the plication software deal with similar data but one can expect
proposed reference architecture including resource models, all this data is differently named and organized. Our goal
security architecture, high-level requirements and gave pro- is to provide fast adapter production for data exchange and
tocol examples. This group has also defined the manage- extraction of these data types used in common software ap-
ment use cases for the lifecycle of a cloud service and the plications and to cover the four categories of interoperability
data artifacts used in the use cases [9]. described by Kumar [12]. The idea is to create a general
The work of Open Cloud Standards Incubator is still in data and process model that includes the most used service
progress, developing slowly. They are working for almost provider in the given class of software and with the use of
three years and yet they have not completed their task. And semantics to create alignment of the data.
even if they do there is no guarantee that this model will be
adopted by other venders that are not part of this group, 4. COMPARISON ANALYSIS OF CCI
like Amazon. MODELS
Table 1 presents the results of evaluation we have provided
3.5 Software and Data Interoperability in order to compare these models. The methodology consist
The interoperability of the Software as a Service (SaaS) by measuring the indicators for the following categories:
layer has not being analyzed as other platforms by researchers.
In [12] this question is raised and initially set to the research • CC stack Layer - An indicator that tells which layer
community in 2010. According to this paper SaaS CCI issue of the CC stack is addressed in the model (for example,
can be summarized into four categories (shown in Figure 7): it can specify IaaS, PaaS or SaaS),
33
Table 1: Model Comparison
Model CC stack Layer Details Realization Acceptance
Cloud Broker IaaS Existing draft of re- Demo realization with Rejected by biggest
quirements and draft Amazon EC2 and Eno- CSP
OWL Ontology maly ECP
Orchestration layer IaaS,PaaS,SaaS General model Early adopters: Cordys, Not accepted by biggest
RightScale and CSC CSP
Blueprint for the In- IaaS Only directions No No public opinion
tercloud
DMTF CIMI IaaS Draft documentation Expected Acceptance expected
Adapters SaaS CSP API or Service re- Some existing realiza- No acceptance nedded
quired tions, many possibilities
• Depth - An indicator that explains the depth of de- [3] D. Bernstein, E. Ludvigson, K. Sankar, S. Diamond,
scription to which the model has published the require- and M. Morrow. Blueprint for the intercloud -
ments, architectures, how detailed is the model, etc protocols and formats for cloud computing
. . . (for example, it can be general model specification, interoperability. In 2009 Fourth International
directions only, draft documentations, etc.) Conference on Internet and Web Applications and
Services, 2009.
• Realization - An indicator that presents the existence [4] N. Bridge, G. Pro, and . Group. 2011 future of cloud
of demo realization, or initial implementation of the computing survey results, 2011.
Cloud Service Providers (CSP) or accepted and incor- [5] Cordys. Now is the time to take the cloud seriouslyy,
porated by the CSP, 2011.
[6] DMTF. Dmtf to develop standards for managing a
• Acceptance - An indicator that shows the possibility cloud computing environment, Apr. 2009.
of acceptance by the biggest Cloud Service Providers
[7] DMTF. Interoperable clouds, Nov 2009.
(CSP).
[8] DMTF. Architecture for managing clouds, Oct. 2010.
We can conclude that the only solution that can be possi- [9] DMTF. Use cases and interactions for managing
bly generally used and adopted by the most of the vendors in clouds, Jun. 2010.
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[2] Cloud interoperability, 2011.
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