1 toward a unified ontology of cloud computing (p6) review by: hossein kalantar youseff, l.;...

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Toward a Unified Ontology of Cloud Computing (P6)

Review by:Hossein Kalantar

Youseff, L.; Butrico, M.; Da Silva, D.; "Toward a Unified Ontology of Cloud Computing," Grid Computing Environments Workshop, 2008. GCE '08 , vol., no., pp.1-10, 12-16 Nov. 2008

CSCI 7799/ Topics in Networked Computing /Fall 2012

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Ontology

• “philosophical ontology has inspired CS/ISresearchers to define and formally represent the description of specific domains. The resulting formaldescriptions, often referred to as domain ontologies, capture the domain invariants and allow different ISs in the same domain to share the common domain knowledge to ensure consistency in applications and enable true interoperability.”From: Jian Guan, Alan S. Levitan, John R. Kuhn Jr., How AIS can progress along with ontology research in IS, International Journal of Accounting Information Systems, Available online 12 September 2012, ISSN 1467-0895, 10.1016/j.accinf.2012.08.002. (http://www.sciencedirect.com/science/article/pii/S1467089512000589)

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Google trend

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Motivation

• Helping the research community achieve a better understanding of cloud computing technology

– First attempts to establish a detailed ontology of the cloud– This approach is to determine the different layers and

components that make the cloud, and study their characteristics in light of their dependency on the other computing fields and models.

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Methodology of classification

• They use composibility as their methodology– Composibility:ability to compose one cloud service from one or

more other cloud services.– It enables proposed ontology to capture the inter-relations

between the different cloud components.– Borrow this method from the principle of composibility in SOA

• why using composibility?– Allows researchers in cloud computing to define a more robust

interaction model between the different cloud entities, on both the functional and semantic levels.

– It facilitates recognizing the inter-dependency between the different cloud systems

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The Cloud Ontology

• Proposed ontology to be envisioned as a stack of layers. Each layer encompasses one or more cloud services. Cloud services belong to the same layer if they have equivalent levels of abstraction, as evident by their targeted users

• By composability, they classify one cloud layer to be higher in the cloud stack, if its services can be composed from the services of the underlying layer

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Cloud Application(e.g. SaaS)

Cloud Software Environment(e.g. PaaS )

The Cloud Ontology

Firmware / Hardware (HaaS)

Software Kernel

Cloud Software Infrastructure

Computational Resources (IaaS)

Storage(DaaS)

Communications(CaaS)

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Cloud Application(e.g. SaaS)

The Cloud Ontology

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Cloud Application Layer

• Cloud applications can be developed on the cloud software environments or infrastructure components

• Cloud applications can be composed as a service from other cloud services offered by other cloud systems using the concepts of SOA– Cloud applications targeted for higher layers in the stack are

simpler to develop and have a shorter time-to-market– Cloud applications become less error-prone since all their

interactions with the cloud are through pretested APIs– Security (safety of storing confidential data, users

authentication and authorization, up-time and performance, as well as data backup and disaster recovery) and availability

– Integration of legacy applications and the migration of the users’ data to the cloud

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Cloud Application(e.g. SaaS)

Cloud Software Environment(e.g. PaaS )

The Cloud Ontology

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Cloud Software Environment Layer(software platform layer)

• Providers of the cloud software environments supply the developers with a programming-language-level environment with a set of well-defined APIs to facilitate the interaction between the environments and the cloud applications, as well as to accelerate the deployment and support the scalability needed of those cloud applications.– Including automatic scaling and load balancing, as well as integration with

other services (e.g. authentication services, email services, user interface) much of the overhead of developing cloud applications is alleviated and is handled at the environment level

– Developers have the ability to integrate other services to their applications on-demand

– Makes the cloud application development a less complicated task, accelerates the deployment time and minimizes the logic faults in the application

– Lock in vendors , offline application development

Lawton, G.; , "Developing Software Online With Platform-as-a-Service Technology," Computer , vol.41, no.6, pp.13-15, June 2008

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Cloud Application(e.g. SaaS)

Cloud Software Environment(e.g. PaaS )

The Cloud Ontology

Cloud Software Infrastructure

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Cloud Software Infrastructure

• The two highest levels in the cloud stack can bypass the cloud infrastructure layer in building their system. Although this bypass can enhance the efficiency of the system, it comes at the cost of simplicity and development efforts

• Cloud services offered in this layer can be categorized into: – Computational Resources– Data Storage– Communications

• Several common design features are shared between the three infrastructure components. security of the services, their availability and quality are among the most commonly addressed concerns for these cloud infrastructure components.

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Cloud Application(e.g. SaaS)

Cloud Software Environment(e.g. PaaS )

The Cloud Ontology

Cloud Software Infrastructure

Computational Resources (IaaS)

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Computational ResourcesInfrastructure as a Service (IaaS)

• Virtual machines (the most common form for providing computational resources to cloud users at this layer)– Allows the users extraordinary flexibility in configuring their

settings while protecting the physical infrastructure of the provider's data center

– Lack of a strict performance isolation between VMs sharing the same physical node has resulted in the inability of cloud providers to give strong guarantees for performance to their clients. Such weak guarantees, unfortunately, can inject themselves up the layers of the cloud stack, and affect the SLAs of the cloud systems built above the IaaS's SLAs.

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Cloud Application(e.g. SaaS)

Cloud Software Environment(e.g. PaaS )

The Cloud Ontology

Cloud Software Infrastructure

Computational Resources (IaaS)

Storage(DaaS)

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Data StorageData-Storage as a Service (DaaS)

• Allows users to store their data at remote disks and access them anytime from any place.– Data storage systems are expected to meet several

rigorous requirements for maintaining users’ data and information, including high availability, reliability, performance, duplication and data consistency.

– Because of the conflicting nature of these requirements, no one system implements all of them together

– DaaS implementing their system to favor one feature over the others

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Cloud Application(e.g. SaaS)

Cloud Software Environment(e.g. PaaS )

The Cloud Ontology

Cloud Software Infrastructure

Computational Resources (IaaS)

Storage(DaaS)

Communications(CaaS)

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CommunicationCommunication as a Service (CaaS)

• Communication becomes a vital component of the cloud infrastructure

• Cloud systems are obliged to provide some communication capability that is service oriented, configurable, schedulable, and reliable

• Supports network QOS, security, dynamic provisioning of virtual overlays for traffic isolation or dedicated bandwidth, guaranteed message delay, communication encryption, and network monitoring

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Cloud Application(e.g. SaaS)

Cloud Software Environment(e.g. PaaS )

The Cloud Ontology

Software Kernel

Cloud Software Infrastructure

Computational Resources (IaaS)

Storage(DaaS)

Communications(CaaS)

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Software Kernel (Virtualization Layer - called by others)

• This cloud layer provides the basic software management for the physical servers that compose the cloud

• Software kernels at this level can be implemented as an OS kernel, hypervisor, virtual machine monitor and/or clustering middleware

• Customarily, grid computing applications were deployed and run on this layer on several interconnected clusters of machines

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Cloud Application(e.g. SaaS)

Cloud Software Environment(e.g. PaaS )

The Cloud Ontology

Firmware / Hardware (HaaS)

Software Kernel

Cloud Software Infrastructure

Computational Resources (IaaS)

Storage(DaaS)

Communications(CaaS)

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Hardware and Firmware

• Is the actual physical hardware and switches that form the backbone of the cloud

• HaaS provider operates, manages and upgrades the hardware on behalf of its consumers, for the life-time of the sublease– Enterprises do not need to invest in building and managing

data centers– Challenges: efficiency, ease and speed of provisioning such

large scale systems, data center management, scheduling, and power-consumption optimizations

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Summary Of Examples Of Some Contemporary Cloud Computing Systems

Cloud Layer Examples of Commercial Cloud Systems

Cloud Application Layer Google Apps and Salesforce Customer Relation Management (CRM) system

Cloud Software Environment Google App Engine and Salesforce Apex System

Cloud Software Infrastructure Computational Resources: Amazon's EC2, Enomalism Elastic Cloud.

Storage: Amazon's S3, EMC Storage Managed Service.

Communication: Microsoft Connected Service Framework (CSF).

Software Kernel Grid and Cluster Computing Systems like Globus and Condor.

Firmware / Hardware IBM-Morgan Stanley's Computing Sublease, and IBM's Kittyhawk Project.

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Discussion

• Pricing models for the different cloud services have taken one of three forms: tiered pricing, per-unit pricing and subscription-based pricing.

• Among the substantial challenges that hinders the wide adoption of cloud computing are the security and privacy concerns of the data in the cloud. In addition, data ownership are among the significant obstacles to cloud computing. Robust monitoring system is other challenge that must be in place to allow the cloud services to actively react to failures.

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Paper contribution

• Proposed cloud ontology and described the different layers of our classification and the relationships between them

• Identified the users/ providers of each cloud layer• Explicated the challenges and trade-offs encountered

by the providers of the cloud services at each level of the stack

• Counts different business models in cloud based systems

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Evaluation

+ Simplicity + Using the popular concept for classification - Lack of coherency for describing sub sections - Lack of cloud definition - Missing important concepts such as: different cloud

computing models (public, private, hybrid)

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Thank You !

Q & A

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Difference between Taxonomies and Ontologies

• Put simply, an ontology is a specification of the characteristics of a domain. In other words, precisely what it mean for something to be in a particular domain.

• A taxonomy is simply a hierarchical categorization or classification of entities within a domain.

• Jack Krupansky (Independent Computer Software Developer)