CHAPTER 8
CLOUD COMPUTING
SE 458
Topics
Cloud Computing
Essential Characteristics
Cloud Service Delivery Models
Software as a Service (SaaS)
Platform as a Service (PaaS)
Infrastructure as a Service (IaaS)
Cloud Deployment Models
SOA vs. Cloud Computing
Virtualization
Benefits of Cloud Computing
Risks of Cloud Computing
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Introduction
Continuing demand for business expansion.
Invest in stand alone servers or software.
These resources are usually underutilized.
They become quickly obselete.
~ 70% of IT investment on maintenance.
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Cloud Computing
Reduces IT complexity by leveraging the efficient pooling of on-demand, self-managed virtual
infrastructure, consumed as a service.
Delivery of resources
Dynamically scalable
Virtualized
Provided as a service over the Internet
Decoupling the delivery of computing services from their underlying technology.
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Cloud Computing
Defined by National Institute of Standards and Technology (NIST) as:
“A consumption and on-demand delivery computing paradigm that enables convenient network access to a shared pool of configurable and often virtualized
computing resources (e.g. networks, servers, storage, middleware and applications as services) that can be rapidly provisioned and released with minimal
management effort or service provider interaction.”
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Business Benefits
Almost zero up-front infrastructure investment.
Just-in-time infrastructure.
More efficient resource utilization.
Elastic capacity (scale up or down).
Usage based costing.
Reduction in application processing time.
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Essential Characteristics
On demand self-service.
Ubiquitous network access.
Location independent resource pooling.
Rapid elasticity and provisioning.
Pay-per-use measured service.
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Cloud Service Delivery Models
Usually 3 models of service delivery.
Software as a Service (SaaS)
Platform as a Service (PaaS)
Infrastructure as a Service (IaaS)
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Cloud Service Delivery Models
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Infrastructure as a Service (IaaS)
Lowest layer.
A means of delivering very basic computing
capability machines with operating systems and storage as services over the network.
Offers computational services so that users can use CPU cycles or storage space without buying
computing or storage devices.
Example: Amazon Web Services with
Elastic Compute Cloud (EC2)
Simple Storage Service (S3)
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Platform as a Service (PaaS)
Between IaaS and SaaS.
Environment where developers build and run an application platform in the cloud, using whatever pre-built components and interfaces that
particular platform provides as a service to developers over the Web.
Examples: Google App Engine and Force.com.
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Software as a Service (SaaS)
On-demand application delivery model over the Internet built upon the underlying IaaS and PaaS layers.
Essentially software applications that are owned, delivered, and managed remotely by one or more software providers.
Examples: SalesForce.com (offers CRM
applications) and Amazon Fulfillment Web Service.
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Cloud Deployment Models
3 major cloud deployment models.
Public cloud
Private cloud
Hybrid cloud
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SOA vs. Cloud Computing
SOA is an architecture pattern, while the cloud is a target deployment platform for that architecture pattern.
Cloud computing provides computing resources and platforms that SOA applications require but an
organization does not own.
Both SOA and Cloud Computing share concepts of service orientation.
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SOA vs. Cloud Computing
Cloud processing and cloud storage are natural target platforms for SOA application deployment.
Modern SOA applications require that services are
Designed to be location independent,
Implementation neutral,
Distributed (protentially heterogenous).
When the service implementation infrastructure is realized inside-the-cloud, these 3 options are
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Virtualization
Technique of managing systems and resources functionally, regardless of their physical layout or location, and hiding their physical characteristics from the way in which other systems, applications or end users interact with them.
It makes the attributes of Cloud Computing possible:
Scalability,
Elasticity,
Share-ability.
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Virtualization
Makes a single physical resource appear to function as multiple logical resources.
A server, an operating system, an application, or storage device.
Makes multiple physical resources appear as a single logical resouces.
Storage devices or servers.
Permits multiple users and applications to share
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Types of Virtualization
Network Virtualization
Server Virtualization
Server Clustering
Storage Virtualization
Application Virtualization
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Components of Virtualization Environment
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Potential Benefits of Cloud Computing
Cost reduction/avoidance
Shifting of resources towards higher value activities
Enhanced service delivery
Agility and scalability
Efficiency
Resiliency
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Potential Risks of Cloud Computing
Cloud service outages
Lack of interoperability between computing clouds
Lack of compatibility with existing applications
IT policy concerns
Security and privacy risks
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Summary
Cloud Computing is a computing paradigm and an associated set of business models used to provide on demand access to a shared pool of
configurable, scalable computing resources
delivered as a service to external customers via the Internet.
Services include storage, processing, memory, network bandwidth, and virtual machines.
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