Service level agreement in cloud computing an overview

Dr Neelesh Jain
Professor
Sagar Institute of Research
Technology & Science
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Service Level Agreement in Cloud
Computing: An Overview

Dr. Neelesh Jain 8770193851 Follow me: Youtube/FB : DrNeeleshjain
Introduction:
Cloud computing is an internet based computing, providing the on demand self
services over the internet for the use of servers, storage space or disk, different
platforms and applications to any cloud user. The cloud computing services are `Pay
as per your usage' based on the agreement between the Cloud Service Provider and
Cloud customer. Service Level Agreement (SLA) is a contract between service
provider and the third party such as Cloud user or Broker(agent), where service
conditions are formally or legally defined. Oftenly Service Level Agreement(SLA) is
used to define the terms of the delivery period of the service, and the different
performance parameters of service to be provided by the provider.

Benefits of Cloud Computing
Cloud Computing has numerous advantages. Some of them are listed below -
● One can access applications as utilities, over the Internet.
● One can manipulate and configure the applications online at any time.
● It does not require to install a software to access or manipulate cloud application.
● Cloud Computing offers online development and deployment tools, programming
runtime environment through PaaS model.
● Cloud resources are available over the network in a manner that provide platform
independent access to any type of clients.
● Cloud Computing offers on-demand self-service. The resources can be used
without interaction with cloud service provider.
● Cloud Computing is highly cost effective because it operates at high efficiency with
optimum utilization. It just requires an Internet connection
● Cloud Computing offers load balancing that makes it more reliable.

Necessity of Cloud Computing.
● The Availability Of Resources.
● The Flexibility Of Providing The IT Services In Cloud Computing.
● The Ability Of Refreshing An Aging Infrastructure With Less Price.
● Economically Supporting For New IT Services And Many User.
● Freeing The Staff Members And To Be Engaged In Other Projects.

Importance of SLA
● The consumer can get the information about the service providers.
● SLA describes the complete information about the service and the type of services (SaaS,
PaaS, IaaS) that are provided to a particular consumer.
● SLA describes the purpose and objectives based on business level policies, which includes
the part of the service provider and the customer.
● The consumers will be able to identify the key security and management strategies of
agreement.
● SLA is used to monitor the quality of service, performance, response time from the service
point of view.
● The consumer can get the idea about the requirements for the management of the service
in case of poor performance.

Service level agreements in Cloud computing
A Service Level Agreement (SLA) is the bond for performance negotiated between
the cloud services provider and the client. Earlier, in cloud computing all Service Level
Agreements were negotiated between a client and the service consumer. Nowadays,
with the initiation of large utility-like cloud computing providers, most Service Level
Agreements are standardized until a client becomes a large consumer of cloud
services. Service level agreements are also defined at different levels which are
mentioned below:
● Customer-based SLA
● Service-based SLA
● Multi level SLA

TYPES OF SLA
Service-level agreement provides a framework within which both seller and buyer
of a service can pursue a profitable service business relationship. It outlines the
broad understanding between the service provider and the serviceconsumer for
conducting business and forms the basis for maintaining a mutually beneficial
relationship. From a legal perspective, the necessary terms and conditions that
bind the service provider to provide services continually to the service consumer
are formally defined in SLA.
There are two types of SLAs from the perspective of application hosting.
1. Infrastructure SLA
2. Application SLA

KEY COMPONENT OF SERVICE-LEVEL AGREEMENT

TYPES OF SLA
There are two types of SLAs from the perspective of application
hosting.
1. Infrastructure SLA
2. Application SLA
Infrastructure SLA.
The infrastructure provider manages and offers guarantees on
availability of the infrastructure, namely, server machine,
power,network connectivity, and so on. Enterprises manage
themselves, their applications that are deployed on these server
machines. The machines are leased to the customers and are isolated
from machines of other customers.

TYPES OF SLA
Infrastructure SLA: Key Contractual Elements of an Infrastructural SLA

TYPES OF SLA
Application SLA.
In the application co-location hosting model, the server
capacity is available to the applications based saolely on their
resource demands.Hence, the service providers are ﬂexible in
allocating and de-allocating computing resources among the
co-located applications. Therefore, the service providers are
also responsible for ensuring to meet their customer’s
application SLOs. For example, an enterprise can have the
following application SLA with a service provider for one of its
application, as shown in Table

TYPES OF SLA
Application SLA: Key Contractual Elements of an Infrastructural SLA

LIFE CYCLE OF SLA
Each SLA goes through a sequence of steps starting from
identification of terms and conditions, activation and monitoring of
the stated terms and conditions, and eventual termination of
contract once the hosting relationship ceases to exist. Such a
sequence of steps is called SLA life cycle and consists of the
following five phases:
1. Contract definition
2. Publishing and discovery
3. Negotiation
4. Operationalization
5. De-commissioning

Literature Review
LinIin et al [l] mentioned the four main goals with respect to SLA -
Oriented Utility Computing i.e. The Customer driven management
of service support, identifying computational risk, suitable
strategies for managing the resources and computation
management of risk.
Yun et al[3] discussed the profit oriented issues and weak point in
traditional technologies.
Slavatore et al[5] presented that applications should act in support
of their users and should be able to make the available cloud
services in SLA negotiation and management.

Literature Review
Rajkumar et al[7] discussed the hierarchical scheduling, and
the need of job prioritization.
Sherif et al[8] presented that in the fast growing and unpredictable
environments, the approaches are based on capacity planning and
workload forecasting techniques, that are in challenging conditions.

Issues and Challenges
1. Computation management of risk to maintain the allocation of
resources based on SLA [1].
2. Applications should act in care of their customers and should
be capable to make the accessible cloud services in SLA
negotiation [5].
3. User waiting in the queue for a long period to avail service [7].
4. Performance of the service affected because of peak level of
workload. The customers will not be satisfied because of poor
performance and the income will be affected [8].
5. Service cost related problems [8].
6. Not providing the specified amount of resources [21]

Conclusion and Future Enhancement
SLA is a legal, formal and negotiated document that defines the
service in terms of quantitative and qualitative metrics. The metrics
which is involved in SLA should be proficient of being measured on a
consistent basis, and the SLA should be evaluated by that metrics.
SLA plays a role in the life cycle of the service. SLA cannot
guarantee that the consumer can access the service as described in
the SLA document. In future our work is focused on developing a
approach to certify that the service is provided according the
specified level of quality which is mentioned in the SLA.

References
[1]Linlin Wu and Rajkumar Buyya, "Service Level Agreement(SLA) in Utility Computing Systems", Technical Report CLOUDS-TR-2010-5, Cloud
Computing and Distributed Systems Laboratory, The University of Melbourne, Australia, September 3, 2010.
[2] Jerry Gao, Xiaoying Bai and Wei-Tek Tsai, "Cloud Testing- Issues, Challenges, Needs and Practice" Software Engineering: An International Journal
(SEIJ), SEPTEMBER 2011 , Vol. I, No. I, pp. 9-23 .
[3] Yun Chi, Hyun Jin Moon, Hakan Hacigumus and Junichi Tatemura, "SLA - Tree : A framework for Efficiently Supporting SLA-based Decisions in Cloud
Computing", Proceedings of the 14th International Conference on Extending Database Technology, 2011 , ISBN: 978-1- 4503-0528-0, Pages 129-140.
[4] "SLA-based Cloud Framework", https://sites.google.com/site/gistcloudresearchgroup/services, Presented By GIST Cloud Computing Research Group.
[5]Salvatore Venticinque, Rocco Aversa, Beniamino di Martino Massimiliano Rak and Dana Petcu, "A cloud Agency for SLA Negotiation and
Management", Euro-Par 2010 Parallel Processing Workshops Lecture Notes in Computer Science Volume 6586, 2011 , Online ISBN : 978-3-642-21878-
1, Print ISBN : 978-3-642-21877-4, pp.587-594.
[6] Service Level Agreement, http://en.wikipedia.orglwiki/Service- level_agreement.
[7] Rajkumar Rajavel and Mala, "Achieving Service Level Agreement in Cloud Environment using Job Prioritization in Hierarchical Scheduling",
Proceedings of the International Conference on Information Systems Design and Intelligent Applications 2012 (INDIA 2012) held in Visakhapatnam, India,
January 2012, Pint ISBN : 978-3-642-27442-8, Online ISBN : 978-3-642-27443-5, Series ISSN : 1867-5662, pp 547-554.
[8] Sherif Sakr, Anna Liu, "SLA-Based and Consumer-centric Dynamic Provisioning for Cloud Databases", CLOUD, IEEE Sixth International Conference
on Cloud Computing, 2013 , doi : I O. 1l09/CLOUD.2012. I I , ISBN: 978-1-4673-2892-0, pp. 360-367.
[9] Pankesh Patel, Ajith Ranabahu, and Amit Sheth, "Service Level Agreement in Cloud Computing", OOPSLA Cloud Computing workshop,
http://corescholar.libraries.wright.edu/knoesis/78.
[10] Linlin Wu, Saurabh Kumar Garg, Steve Versteeg and Rajkumar Buyya, "SLA-based Resource Provisioning for Software-as-a-Service Applications
in Cloud Computing Environments", 11th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing, 2011 , ISBN 978-0-7695-4395-6/ 11
, pp. 195-204.
[11] Dimension data white paper, "Comparing Public Cloud Service Level
Agreements Questions to ask when evaluating public cloud SLAs",
http://cloud.dimensiondata.com/sites/defaultlfiles/comparing_public_clou
d_serviceJevel_agreements_O_O.pdf, CS 1 DDMS-1249 1 02113 ©
Copyright Dimension Data 2013.
[12] "Amazon

References
[11] Dimension data white paper, "Comparing Public Cloud Service Level Agreements Questions to ask when evaluating public cloud SLAs",
http://cloud.dimensiondata.com/sites/defaultlfiles/comparing_public_cloud_serviceJevel_agreements_O_O.pdf, CS 1 DDMS-1249 1 02113 © Copyright Dimension Data
2013.
[12] "Amazon EC2 Service Level Agreement", http://aws.amazon.com/ec2/slal, Effective Date: J une I, 2013. [13] CIS CO, "Managing the Real Cost of On-Demand
Enterprise Cloud Services with Chargeback Models", By Cisco, Aug 2010, http://www.cisco.com/en/US/services/ps29611psl 0364/ps 103 70/ps III 04 ICloud_
Services_Chargeback _ Models_ White_Paper.pdf
[14] Rajkumar Buyya, Saurabh Kumar Garg and Rodrigo N. Calheiros, "SLA-Oriented Resource Provisioning for Cloud Computing : Challenges, Architecture, and
Solutions", CSC 'li Proceedings of the 2011 International Conference on Cloud and Service Computing, IEEE Computer Society Washington, DC, USA ©2011 ISBN : 978-1-
4577- 1635-5, pp. 1-10.
[15] Myerson, "Best Practices To Develop SLAs For Cloud Computing", Retrieved From http://www.ibm.com/developerworks/cioud/libraryl clslastandards/, January 2013.
[16] Linlin Wu, Saurabh Kumar and Rajkumar Buyya, "SLA-based Resource Allocation for Software as a Service Provider(SaaS) in Cloud Computing Environments",
Proceeding CCGRID 'lI Proceedings of the 2011 11th TEEE/ACM International Symposium on Cluster, Cloud and Grid Computing, IEEE Computer Society Washington,
DC, USA ©2011 , ISBN: 978-0-7695-4395-6, pp. 195-204.
[17] Mitchell Cochran and Paul D. Witman, "Governance and Service Level Agreement Issues in a Cloud Computing Environment" Journal of Information Technology
Management, 20 11 , Volume XXII, Number 2, ISSN # I 042-1319, pp. 41-55 .
[18] Dr. Angel Luis Diaz, "Service Level Agreements in the Cloud: Who cares?" Retrieved From ..http://www.wired.com/20 11 112/service-level-agreements-in-the-cloud-
who-cares/", 14 December 2011.
[19] Stefano Ferretti, Vittorio Ghini, Fabio Panzieri, Micheie Pellegrini and Elisa Turrini, "QoS - Aware Clouds", 2010 IEEE 3rd International Conference on Cloud
Computing, 20 10 IEEE, pp. 321-328.
[20] Pankesh Patel, Ajith Ranabahu and Amit Sheth, "Service Level Agreement in Cloud Computing", Report, Core Wright university Libraries, Kno.e.sis Publications, 2009.
[21] Ryan Houlihan, Xiaojiang Du, Chiu C. Tan, Jie Wu and Mohsen Guizani , "Auditing Cloud Service Level Agreement on VMCPU Speed", In proceedings of IEEE
international Conference on Communications (ICC), 2014, INSPEC Accession Number:14545672, DOI:IO.II09/ICC .2014.6883417 , pp. 799-803.
[22] Mario Mac ' las, J. Oriol Fit'o and Jordi Guitart, "Rule-based SLA Management for Revenue Maximisation in Cloud Computing Markets", International Conference on
Network and Service Management - CNSM , 2010, ISBN 978-1-4244-8909-1 pp. 354-357. [23] PCI DSS Compliance in a Cloud Computing Environment, http://zinatull
in.com/20 13/03.

Service level agreement in cloud computing an overview

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