ABSTRACT
The term “cloud computing" is a recent
buzzword in the IT world. Behind this
fancy poetic phrase there lies a true picture
of the future of computing for both in
technical perspective and social perspective.
Though the term “Cloud Computing" is
recent but the idea of centralizing
computation and storage in distributed data
centres maintained by third party companies
is not new but it came in way back in 1990s
along with distributed computing
approaches like grid computing. Cloud
computing is aimed at providing IT as a
service to the cloud users on-demand basis
with greater flexibility, availability,
reliability and scalability with utility
computing model. This new paradigm of
computing has an immense potential in it to
be used in the field of e-governance and in
rural development perspective in developing
countries like India.
INTRODUCTION
Cloud computing is the next natural
step in the evolution of on-demand
information technology services and
products. To a large extent cloud computing
will be based on virtualized resources. The
idea of cloud computing is based on a very
fundamental principal of `reusability of IT
capabilities`. The difference that cloud
computing brings compared to traditional
concepts of grid computing‖, distributed
computing‖, utility computing‖, or
autonomic computing is to broaden horizons
across organizational boundaries.
According to the IEEE Computer Society
Cloud Computing is:
"A paradigm in which information is
permanently stored in servers on the
Internet and cached temporarily on clients
that include desktops, Entertainment
centres, table computers, notebooks, wall
computers, handhelds, etc."
CLOUD COMPUTING
KRISHNALAL K J
S5 MCA
Sree Narayana Guru Institute Of Science And Technology ,North Paravur
krishnalalkj@gmail.com
Though many cloud computing
architectures and deployments are powered
by grids, based on autonomic characteristics
and consumed on the basis of utilities
billing, the concept of a cloud is fairly
distinct and complementary to the concepts
of grid, SaaS, Utility Computing etc. In
theory, cloud computing promises
availability of all required hardware,
software, platform, applications,
infrastructure and storage with an ownership
of just an internet connection.
People can access the information
that they need from any device with an
Internet connection including mobile and
handheld phones rather than being chained
to the desktop. It also means lower costs,
since there is no need to install software or
hardware.
Cloud Computing Basics
Cloud computing is a paradigm of
distributed computing to provide the
customers on-demand, utility based
computing services. Cloud users can provide
more reliable, available and updated services
to their clients in turn. Cloud itself consists
of physical machines in the data centres of
cloud providers. Virtualization is provided
on top of these physical machines. These
virtual machines are provided to the cloud
users. Different cloud provider provides
cloud services of different abstraction level.
E.g. Amazon EC2 enables the users to
handle very low level details where Google
App-Engine provides a development
platform for the developers to develop their
applications. So the cloud services are
divided into many types like Software as a
Service, Platform as a Service or
Infrastructure as a Service. These services
are available over the Internet in the whole
world where the cloud acts as the single
point of access for serving all customers.
Cloud computing architecture addresses
difficulties of large scale data processing.
Types of Cloud
Cloud can be of three types--
A) Private Cloud: This type of cloud is
maintained within an organization and used
solely for their internal purpose. So the
utility model is not a big term in this
scenario. Many companies are moving
towards this setting and experts consider this
is the 1st step for an organization to move
into cloud. Security, network bandwidth are
not critical issues for private cloud.
B). Public Cloud: In this type an
organization rents cloud services from cloud
provider’s on-demand basis. Services
provided to the users using utility computing
model.
C) Hybrid Cloud: This type of cloud is
composed of multiple internal or external
cloud. This is the scenario when an
organization moves to public cloud
computing domain from its internal private
cloud.
Cloud Stakeholders
To know why cloud computing is used
let's first concentrate on who use it. And
then we would discuss what advantages they
get using cloud.
There are three types of stakeholders
cloud providers, cloud users and the end
users [Figure 1]. Cloud providers provide
cloud services to the cloud users. These
cloud services are of the form of utility
computing i.e. the cloud users uses these
services pay-as-you-go model. The cloud
users develop their product using these
services and deliver the product to the end
users.
Fig 1: Interconnection between cloud
stakeholders
Advantages of using Cloud
The advantages for using cloud
services can be of technical, architectural,
business etc.
1) Cloud Providers' point of view
(a) Most of the data canters today are
underutilized. They are mostly 15% utilized.
These data canters need spare capacity just
to cope with the huge spikes that sometimes
get in the server usage. Large companies
having those data canters can easily rent
those computing power to other
organizations and get profit out of it and also
make the resources needed for running data
center (like power) utilized properly.
(b) Companies having large data centers
have already deployed the resources and to
provide cloud services they would need very
little investment and the cost would be
incremental.
2) Cloud Users' point of view
(a) Cloud users need not to take care about
the hardware and software they use and also
they don't have to be worried about
maintenance. The users are no longer tied to
someone’s traditional system.
(b) Virtualization technology gives the
illusion to the users that they are having all
the resources available.
(c) Cloud users can use the resources on
demand basis and pay as much as they use.
So the users can plan well for reducing their
usage to minimize their expenditure.
(d) Scalability is one of the major
advantages to cloud users. Scalability is
provided dynamically to the users. Users get
as much resources as they need. Thus this
model perfectly fits in the management of
rare spikes in the demand.
Motivation towards Cloud in recent
time
Cloud computing is not a new idea
but it is an evolution of some old paradigm
of distributed computing. The advent of the
enthusiasm about cloud computing in recent
past is due to some recent technology trend
and business models.
1. High demand of interactive
applications with real time response
and with capability of providing
information either by other users or
by nonhuman sensors gaining more
and more popularity today. These are
generally attracted to cloud not only
because of high availability but also
because these services are generally
data intensive and require analysing
data across different sources.
2. Parallel batch processing Cloud
inherently supports batch-processing
and analysing tera-bytes of data very
efficiently. Programming models like
Google's map-reduce and Yahoo!'s
open source counterpart ,Hadoop can
be used to do these hiding
operational complexity of parallel
processing of hundreds of cloud
computing servers.
3. New trend in business world and
scientific community In recent times
the business enterprises are
interested in discovering customers
needs, buying patterns, supply chains
to take top management decisions.
These require analysis of very large
amount of online data. This can be
done with the help of cloud very
easily. Yahoo! Homepage is a very
good example of such thing. In the
homepage they show the hottest
news in the country. And according
to the users' interest they change the
ads and other sections in the page.
Other than these many scientific
experiments need very time
consuming data processing jobs like
LHC (Large Hadron Collider). Those
can be done by cloud.
4. Extensive desktop application ,
Some desktop applications like
Matlab , Mathematical
are becoming so compute intensive
that a single desktop machine is no
longer enough to run them.
So they are developed to be capable
of using cloud computing to perform
extensive evaluations.
Cloud Architecture
Cloud architecture the systems architecture
of the software systems involved in the
delivery of cloud computing, comprises
hardware and software designed by a cloud
architect who typically works for a cloud
integrator. It typically involves multiple
cloud components communicating with each
other over application programming
interfaces, usually web services.
This closely resembles the Unix
philosophy of having multiple programs
doing one thing well and working together
over universal interfaces. Complexity is
controlled and the resulting systems are
more manageable than their monolithic
counterparts.
Cloud architecture extends to the
client, where web browsers and/or software
applications access cloud applications.
Cloud storage architecture is loosely
coupled, where metadata operations are
centralized enabling the data nodes to scale
into the hundreds, each independently
delivering data to applications or users
Fig 2 : Cloud Architecture
Cloud –Types
A) Public cloud:
Public cloud or external cloud
describes cloud computing in the traditional
mainstream. Public clouds are run by third
parties, and applications from different
customers are likely to be mixed together on
the cloud’s servers, storage systems, and
networks. A public cloud provides services
to multiple customers.
B) Hybrid cloud:
Hybrid clouds combine both public
and private cloud models. This is most often
seen with the use of storage clouds to
support Web 2.0 applications.
C) Private cloud:
Private clouds are built for the
exclusive use of one client, providing the
utmost control over data, security, and
quality of service. The company owns the
infrastructure and has control over how
applications are deployed on it. Private
clouds can be built and managed by a
company’s own IT organization or by a
cloud provider
Cloud computing products and services
can be classified into 4 major categories:
They are,
1) Application as service (AaaS)
2) Platform as a Service (PaaS)
3) Infrastructure as a service (IaaS)
4) Software as a Service (SaaS)
1) Application as s service (AaaS): These
are the first kind of cloud computing
services that came into being. Under this, a
service is made available to an end-user. The
end-user is asked to create an account with
the service provider and start using the
application. One of first famous application
was web-based email service by hotmail
started in 1996. Scores of such services are
available now on the web.
2) Platform as a Service (PaaS): Cloud
vendors are companies that offer cloud
computing services and products. One of the
services that they provide is called PaaS.
Under this a computing platform such as
operating system is provided to a customer
or end user on a monthly rental basis. Some
of the major cloud computing vendors are
Amazon, Microsoft, and Google etc.
3). Infrastructure as a service (Iaas): The
cloud computing vendors offer infrastructure
as a service. One may avail hardware
services such as processors, memory,
networks etc on agreed basis for specific
duration and price.
4) Software as a service (SaaS): Software
package such as CRM or CAD/CAM can be
accessed under cloud computing scheme.
Here a customer upon registration is allowed
to use software accessible through net and
use it for his or his business process. The
related data and work may be stored on local
machines or with the service providers. SaaS
services may be available on rental basis or
on per use basis.
Component
The key to a SOA framework that
supports workflows is componentization of
its services, an ability to support a range of
couplings among workflow building blocks,
fault-tolerance in its data and process aware
service based delivery, and an ability to
audit processes, data and results, i.e., collect
and use provenance information.
Component-based approach is characterized
by reusability (elements can be re-used in
other workflows), substitutability
(alternative implementations are easy to
insert, very precisely specified interfaces are
available, run-time component replacement
mechanisms exist, there is ability to verify
and validate substitutions, etc.),
extensibility and scalability (ability to
readily extend system component pool and
to scale it, increase capabilities of individual
components, have an extensible and scalable
architecture that can automatically discover
new functionalities and resources,
etc),customizability (ability to customize
generic features to the needs of a particular
scientific domain and problem), and
composability (easy construction of more
complex functional solutions using basic
components, reasoning about such
compositions, etc.). There are other
characteristics that also are very important.
Those include reliability and availability of
the components and services, the cost of the
services, security, total cost of ownership,
economy of scale, and so on. In the context
of cloud computing we distinguish many
categories of components. From
differentiated and undifferentiated hardware,
to general-purpose and specialized software
and applications, to real and virtual images ,
to environments, to no-root differentiated
resources, to workflow-based environments
and collections of services, and soon.
Virtualization
Virtualization is another very useful
concept. It allows abstraction and isolation
of lower-level functionalities and underlying
hardware. This enables portability of higher-
level functions and sharing and/or
aggregation of the physical resources. The
virtualization concept has been around in
some form since 1960s (e.g., in IBM
mainframe systems). Since then, the concept
has matured considerably and it has been
applied to all aspects of computing memory,
storage, processors, software, networks, as
well as services that IT offers. It is the
combination of the growing needs and the
recent advances in the IT architectures and
solutions that is now bringing the
virtualization to the true commodity level.
Virtualization, through its economy of scale,
and its ability to offer very advanced and
complex IT services at a reasonable cost, is
poised to become, along with wireless and
highly distributed and pervasive computing
devices, such as sensors and personal cell-
based access devices, the driving technology
behind the next wave in IT growth .Not
surprisingly there are dozens of
virtualization products, and a number of
small and large companies that make them.
Some examples in the operating systems and
software applications space are VMware1,
Xen an open source Linux-based product
developed.by XenSource2, and Microsoft
virtualization products, to mention a few.
Major IT players have also shown a renewed
interest in the technology. Classical storage
players such as EMC10, NetApp11, IBM12
and Hitachi13 have not been standing still
either. In addition, the network virtualization
market is teeming with activity.
Users
The most important Cloud entity, and the
principal quality driver and constraining
influence is of course the user. The value of
a solution depends very much on the view it
has of its end-user requirements and user
categories.
There four broad sets of
nonexclusive user categories:
System or Cyber infrastructure (CI)
developers, developers (authors) of different
component services and underlying
applications, technology and domain
personnel that integrates basic services into
composite services and their orchestrations
(workflows) and delivers those to end-users,
and finally users of simple and composite
services. User categories also include
domain specific groups, and indirect users
such as stakeholders, policy makers, and so
on. Functional and usability requirements
derive, in most part, directly from the user
profiles.
Working Of Cloud Computing:
Cloud computing system can be divided it
into two sections: the front end and the back
end. They connect to each other through a
network, usually the Internet. The front end
is the side the computer user, or client, sees.
The back end is the "cloud" section of the
system. On the back end there are various
computers, servers and data storage systems
that create the "cloud" of computing
services. A central server administers the
system, monitoring traffic and client
demands to ensure everything runs
smoothly. It follows set of rules called
protocols
Servers and remote computers do most of
the work and store the data.
Fig 3 : Cloud Computing
Security and privacy
Cloud computing poses privacy concerns
because the service provider can access the
data that is on the cloud at any time. It could
accidentally or deliberately alter or even
delete information. Many cloud providers
can share information with third parties if
necessary for purposes of law and order
even without a warrant. That is permitted in
their privacy policies which users have to
agree to before they start using cloud
services. Solutions to privacy include policy
and legislation as well as end users' choices
for how data is stored. Users can encrypt
data that is processed or stored within the
cloud to prevent unauthorized access.
According to the Cloud Security Alliance,
the top three threats in the cloud are Insecure
Interfaces and API's, Data Loss & Leakage,
and Hardware Failure which accounted for
29%, 25% and 10% of all cloud security
outages respectively - together these form
shared technology vulnerabilities. In a cloud
provider platform being shared by different
users there may be a possibility that
information belonging to different customers
resides on same data server. Therefore
Information leakage may arise by mistake
when information for one customer is given
to other. Additionally, Eugene Schultz, chief
technology officer at Emagined Security,
said that hackers are spending substantial
time and effort looking for ways to penetrate
the cloud. "There are some real Achilles'
heels in the cloud infrastructure that are
making big holes for the bad guys to get
into". Because data from hundreds or
thousands of companies can be stored on
large cloud servers, hackers can theoretically
gain control of huge stores of information
through a single attack — a process he
called "hyper jacking".
There is the problem of legal
ownership of the data (If a user stores some
data in the cloud, can the cloud provider
profit from it?). Many Terms of Service
agreements are silent on the question of
ownership.
Physical control of the computer
equipment (private cloud) is more secure
than having the equipment off site and under
someone else's control (public cloud). This
delivers great incentive to public cloud
computing service providers to prioritize
building and maintaining strong
management of secure services. Some small
businesses that don't have expertise in IT
security could find that it's more secure for
them to use a public cloud.
There is the risk that end users don't
understand the issues involved when signing
on to a cloud service (persons sometimes
don't read the many pages of the terms of
service agreement, and just click "Accept"
without reading). This is important now that
cloud computing is becoming popular and
required for some services to work, for
example for an intelligent personal assistant
(Apple's Siri or Google Now).
Fundamentally private cloud is seen
as more secure with higher levels of control
for the owner; however public cloud is seen
to be more flexible and requires less time
and money investment from the user.
Merits & Demerits
Merits:
Cloud enabler technologies like utility
computing, Grid Computing, RTI, web
infrastructure and others are cloud enabled.
 Infrastructure service providers are
taking advantage of the Cloud
services.
 Information services, entertainment-
oriented services such as video on
demand, simple business services
such as customer authentication or
identity management and contextual
services such as location or mapping
services are positioned well by using
the service.
 Other services, such as corporate
processes (for example, billing,
deduction management and
mortgage calculation) and
transactional services (for example,
fiscal transactions), would take
longer to reach the cloud and the
mainstream.
 Cloud computing infrastructures
allows efficient use of their IT
hardware and software investments
 A cloud infrastructure can be a cost
efficient model for delivering
information services, reducing IT
management complexity.
 The Cloud makes it possible to
launch Web 2.0 applications quickly
and to scale up applications as much
as needed when needed.
Demerits:
Stored data might not be secure: With cloud
computing, all our data is stored on the
cloud. The unauthorized users gain access to
our confidential data.
 Dependent on internet connection:
Internet connectivity isn’t
completely stable and reliable.
 It’s not platform agnostic: Most
clouds force participants to rely on a
single platform or host only one type
of product.
 It Can be slow: Even on a fast
connection, web based application
scan sometimes be slower than
accessing a similar software program
on our desktop PC.
The future
According to Gartner's Hype cycle, cloud
computing has reached a maturity that leads
it into a productive phase. This means that
most of the main issues with cloud
computing have been addressed to a degree
that clouds have become interesting for full
commercial exploitation. This however does
not mean that all the problems listed above
have actually been solved, only that the
according risks can be tolerated to a certain
degree. Cloud computing is therefore still as
much a research topic, as it is a market
offering. What is clear through the evolution
of Cloud Computing services is that the
CTO is a major driving force behind Cloud
adoption. The major Cloud technology
developers continue to invest billions a year
in Cloud R&D; for example, in 2011
Microsoft committed 90% of its $9.6bn
R&D budget to Cloud.
Conclusion
Cloud‖ computing builds on decades
of research in virtualization, distributed
computing, utility computing, and more
recently networking, web and software
services. It implies a service oriented
architecture, reduced information
technology overhead for the end-user, great
flexibility, reduced total cost of ownership,
on demand services and many other things.
In today's global competitive market,
companies must innovate and get the most
from its resources to succeed. Cloud
computing infrastructures are next
generation platforms that can provide
tremendous value to companies of any size.
They can help companies achieve more
efficient use of their IT hardware and
software investments and provide a means to
accelerate the adoption of innovations.Cloud
computing increases profitability by
improving resource utilization. Costs are
driven down by delivering appropriate
resources only for the time those resources
are needed. Cloud computing has enabled
teams and organizations to streamline
lengthy procurement processes.
Cloud computing enables innovation
by alleviating the need of innovators to find
resources to develop, test, and make their
innovations available to the user community.
Innovators are free to focus on the
innovation rather than the logistics of
finding and managing resources that enable
the innovation.
References
 Google app engine.
http://code.google.com/appengine/
 http://www.wikipedia.org/
 http://communication.howstuffworks
.com/cloud-computing2.html
 K.I. Juster-- Cloud Computing Can
Close the Development Gap.
 http://www.salesforce.com/assets/pdf
/misc/IT-development-paper.pdf
.
cloude computing report