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Understanding Cloud
Computing
by Vinod V Menon, ACA, DCFA

Friday, May 18, 2012

Meaning

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Meaning Cloud computing refers to the delivery of computing and storage
capacity as a service to a heterogeneous community of end-recipients.

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History - the beginning
An early but surprisingly complete implementation
of cloud computing was implemented and
patented (in Germany and England) by Hardy
Schloer (which he termed the "one-page web")
with multiple user applications, multiple
identiﬁcation providers, cloud storage, back-end
servers with plug-in applications, a multiple tiered
server architecture able to handle different user
devices over the internet, and built-in security
features.

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History - 2006
After the dot-com bubble, Amazon played a key role in the
development of cloud computing by modernizing their data
centers, which, like most computer networks, were using as
little as 10% of their capacity at any one time, just to leave
room for occasional spikes. Having found that the new cloud
architecture resulted in signiﬁcant internal efﬁciency
improvements whereby small, fast-moving "two-pizza
teams" could add new features faster and more easily,
Amazon initiated a new product development effort to
provide cloud computing to external customers, and
launched Amazon Web Service (AWS) on a utility computing
basis in 2006

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History - 2008
In early 2008, Eucalyptus became the first open-source, AWS API-compatible platform for
deploying private clouds.

In early 2008, OpenNebula, enhanced in the RESERVOIR European Commission-funded
project, became the first open-source software for deploying private and hybrid clouds,
and for the federation of clouds.

In the same year, efforts were focused on providing quality of service guarantees (as
required by real-time interactive applications) to cloud-based infrastructures, in the
framework of the IRMOS European Commission-funded project, resulting to a real-time
cloud environment.

By mid-2008, Gartner saw an opportunity for cloud computing "to shape the relationship
among consumers of IT services, those who use IT services and those who sell
them"and observed that "Organizations are switching from company-owned hardware and
software assets to per-use service-based models" so that the "projected shift to cloud
computing... will result in dramatic growth in IT products in some areas and significant
reductions in other areas."

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Similar Systems?
Autonomic computing

Client–server model

Grid computing

Mainframe computer

Utility computing

Peer-to-peer

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Characteristics?
Multi-tenancy
Agility
Reliability
Application Program Interface
(API)
Scalability and Elasticity
Cost
Performance
Device and location independence
Security
Virtualization
Maintenance

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Service Models

Infrastructure as a service (IaaS)

Platform as a service (PaaS)

Software as a service (SaaS)

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Infrastructure as a
service (IaaS)
In this most basic cloud service model, cloud providers offer computers – as
physical or more often as virtual machines –, raw (block) storage, firewalls ,
load balancers, and networks. IaaS providers supply these resources on
demand from their large pools installed in data centers. Local area networks
including IP addresses are part of the offer. For the wide area connectivity,
the Internet can be used or - in carrier clouds - dedicated virtual private
networks can be configured.

To deploy their applications, cloud users then install operating system
images on the machines as well as their application software. In this model,
it is the cloud user who is responsible for patching and maintaining the
operating systems and application software. Cloud providers typically bill
IaaS services on a utility computing basis, that is, cost will reflect the
amount of resources allocated and consumed.

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Platform as a service
(PaaS)
In the PaaS model, cloud providers deliver a computing
platform and/or solution stack typically including
operating system, programming language execution
environment, database, and web server. Application
developers can develop and run their software solutions
on a cloud platform without the cost and complexity of
buying and managing the underlying hardware and
software layers. With some PaaS offers, the underlying
compute and storage resources scale automatically to
match application demand such that the cloud user does
not have to allocate resources manually.
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Software as a service
(SaaS)
In this model, cloud providers install and operate application software in the cloud and
cloud users access the software from cloud clients. The cloud users do not manage the
cloud infrastructure and platform on which the application is running. This eliminates the
need to install and run the application on the cloud user's own computers simplifying
maintenance and support. What makes a cloud application different from other applications
is its elasticity. This can be achieved by cloning tasks onto multiple virtual machines at run-
time to meet the changing work demand. Load balancers distribute the work over the set of
virtual machines. This process is transparent to the cloud user who sees only a single
access point. To accommodate a large number of cloud users, cloud applications can be
multi-tenant, that is, any machine serves more than one cloud user organization. It is
common to refer to special types of cloud based application software with a similar naming
convention: desktop as a service, business process as a service, Test Environment as a
Service, communication as a service.

The pricing model for SaaS applications is typically a monthly or yearly ﬂat fee per user.

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Cloud Clients

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Deployment models

Public Cloud

Community Cloud

Hybrid Cloud

Private Cloud

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Public cloud - Public cloud applications, storage, and other
resources are made available to the general public by a service provider.

Community cloud - This shares infrastructure between several
organizations from a speciﬁc community with common concerns (security,
compliance, jurisdiction, etc.), whether managed internally or by a third-
party and hosted internally or externally

Hybrid cloud - This is a composition of two or more clouds (private,
community or public) that remain unique entities but are bound together,
offering the beneﬁts of multiple deployment models

Private cloud - Private cloud is cloud infrastructure operated solely
for a single organization, whether managed internally or by a third-party and
hosted internally or externally.

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Cloud architecture

Cloud architecture, the systems architecture of the
software systems involved in the delivery of cloud
computing, typically involves multiple cloud
components communicating with each other over
a loose coupling mechanism such as a messaging
queue. Elastic provision implies intelligence in the
use of tight or loose coupling as applied to
mechanisms such as these and others.

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The Intercloud

The Intercloud is an interconnected global "cloud
of clouds" and an extension of the Internet
"network of networks" on which it is based.

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Cloud engineering
Cloud engineering is the application of
engineering disciplines to cloud computing. It
brings a systematic approach to the high level
concerns of commercialisation, standardisation,
and governance in conceiving, developing,
operating and maintaining cloud computing
systems. It is a multidisciplinary method
encompassing contributions from diverse areas
such as systems, software, web, performance,
information, security, platform, risk, and quality
engineering.
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Issues
Privacy

Compliance

Legal

Open source

Open standards

Security

Sustainability

Abuse
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FUTURE OF CLOUD
COMPUTING

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