B.E CSE IV year(PET Engineering College,Valliyoor)
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B.E CSE IV year(PET Engineering College,Valliyoor)
Email : firstname.lastname@example.org
Cloud computing is a service that helps us to
perform the tasks over the Internet. The users can access
resources as they need them. The term “Cloud” refers the
internet. Cloud computing consists of hardware and
software available on the internet managed by third party
services. The authorized user can reach the cloud for
resources when they need it. The users can manage their
data in cloud by storing it in various devices. It is one of
the best ways to run business. Instead of installing a suite
of software for each computer, we would only have to
load one application. We would Log into a Web-based
service which hosts all the programs. Remote machines
owned by another company would run everything from e-
mail to word processing to complex data analysis
programs. It's called cloud computing
Cloud Computing is basically Internet based
development and making use of computer technology.
The Cloud here stands for the Internet and Computing
basically refers to the Computer Technology to be used. It
is a style of computing in which typically real time
scalable resources are provided as a service over the
Internet to users who need not have knowledge of,
expertise in, or control over the technology infrastructure
that supports them. This concept incorporates Software as
a Service (SaaS)
The term cloud is used as a metaphor for the Internet,
based on how the Internet is depicted in computer
network diagrams, and is an abstraction for the complex
infrastructure it conceals
– Turn on your lights and meter starts
running. Once it is switched off, meter
– You will pay only for the power
The same concept applies in the Cloud Computing. “Pay
for what you use”
Figure 1. Vendors providing Cloud computing
2. Secured Cloud Computing
The data stored in the cloud are accessed by the
authenticated users via passwords or tokens
The users just ‘Plug in’ and access the resources.
The company or the individuals are paying for not
using the system but now they can pay only for the
computing power and services they use.
The online storage is safe and secured.
3. Key Characteristics
Multi-tenancy enables sharing of resources and costs
among a large pool of users.
Centralization of infrastructure in areas
with lower costs (such as real estate, electricity, etc.)
Peak-load capacity increases (users need not engineer
for highest possible load-levels)
Utilization and efficiency improvements for systems
that are often only 10-20% utilized.
On-demand allocation and de-allocation of CPU,
storage and network bandwidth
Performance is monitored and consistent, but can
suffer from insufficient bandwidth or high network
Reliability improves through the use of multiple
redundant sites, which makes it suitable for business
continuity and disaster recovery.
Scalability meets changing user demands quickly
without users having to engineer for peak loads.
4. Cloud Computing Architecture
The below picture describes the basic architecture
of Cloud computing. Major components of the cloud
computing are – “Application servers”, “Data storage”,
“Computer Network”, “Control Node”. When client
application request for a service, control node decides
which application server will be used as well as
determines the from which data storage data will be
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.
Figure 2. Architecture of Cloud Computing
We divide 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. The front end includes the client's
computer (or computer network) and the application
required to access the cloud computing system. Not all
cloud computing systems have the same user interface.
Services like Web-based e-mail programs leverage
existing Web browsers like Internet Explorer or Firefox.
Other systems have unique applications that provide
network access to clients. On the back end of the system
are the various computers, servers and data storage
systems that create the "cloud" of computing services. In
theory, a cloud computing system could include
practically any computer program you can imagine, from
data processing to video games. Usually, each application
will have its own dedicated server. A central server
administers the system, monitoring traffic and client
demands to ensure everything runs smoothly. It follows a
set of rules called protocols and uses a special kind of
software called middleware.
5. Features of cloud computing
In cloud computing, different server can handle
multiple problems at same time. Cloud computing reduces
the infrastructure cost, as individual needs not require to
maintain own server, software. Required infrastructure
will be available over Internet, whenever needed.
Resources will be allocated dynamically during
computing. After completion of the computation or
operation resources will be released. That is why, cloud
computing is often called as on-demand-computing.
Cloud compute improves scalability. There are two
types of scalability: Horizontal scalability and Vertical
scalability. Horizontal scalability handles concurrent user.
And vertical scalability manages consistent performance
of application where load increases. Cloud computing
also offers service level agreement for some of the
6. Business Implications
Enterprise business users’ interest in Cloud
computing comes due to multiple benefits. The Pay-As-
You-Use consumption model traditionally associated with
utility consumption can now be applied to IT – to both the
hardware and, perhaps even more interestingly, to the
business applications themselves. The cloud computing
model converts the traditional capital expenditure model
(CapEx) common in data centers today to an operational
expenditure (OpEx) model.To the business software
vendors cloud is going to be a potential new distribution
channel for their applications.
Cloud computing takes these steps to a new level
and allows an organization to further reduce costs through
improved utilization, reduced administration and
infrastructure costs, and faster deployment cycles. The
cloud is a next generation platform that provides dynamic
resource pools, virtualization, and high availability.
Cloud computing describes both a platform and a
type of application. A cloud computing platform
dynamically provisions, configures, reconfigures, and de-
provisions servers as needed. Cloud applications are
applications that are extended to be accessible through the
Internet. These cloud applications use large data centers
and powerful servers that host Web applications and Web
Figure 3. Cloud Computing Model
7. Types of clouds
Different types of clouds are available to all the users
to utilize the resources.
Figure 4 .Public, private &hybrid cloud
7.1. Public Clouds
Often depicted as from third party provider, "public"
clouds are typically made available via the Internet and
may be free or inexpensive to use. Public cloud also
referred to as “Off Premises”. There are many examples
of these types of clouds, providing services across open,
public networks today such as Google
7.2. Private Cloud
"Private" clouds offer many of the same benefits as
"public" clouds but are managed within the organization.
Public cloud also referred to as “On Premises”. These
types of clouds are not burdened by network bandwidth
and availability issues or potential security exposures that
may be associated with public clouds. Private clouds can
offer the provider and user greater control, security and
7.3. Hybrid Cloud
Combination of both Public (External) and Private
(Internal) Cloud computing.
Figure 5. Enterprise firewall
8. Cloud Computing Implementation
Currently there are two major implementation through
which we can take advantage of cloud computing
• Amazon Web Services (AWS)
• Google Application Engine (GAE)
8.1. Amazon Web Services (AWS)
AWS offers the cloud in 2 levels.
• Computing resources
• Plug in appliances
Computing resources provides processor, memory, file
system, database and messaging. Amazon manages the
computing resources. Amazons partners provide plug in
appliances. Partners’ appliances are free to attach a
surcharge to the resources that implement their offerings.
AWS offers 5 primary services
8.1.1. Elastic Compute cloud (EC2)
It offers virtual machine containing memory and
storage. Virtual machines are Linux variants. Amazon has
started to offer proprietary operating systems such as
Windows server, Oracle Enterprise. The cloud
applications can dynamically allocate & de-allocate the
virtual machines based on the user requirements. EC2
offers 32-bit processor to 64-bit processor in virtual
machines. EC2 is in beta version and does not support
Service Level Agreement. Each virtual machine can be
protected with a configurable firewall called security
8.1.2. Simple Storage Service (S3)
It provides facility to declare buckets and place
data objects into the buckets. Each buckets and objects
maintain a security profile that controls access. Third-
Party tools use the API to provide a file system like view
into the buckets. Each bucket can also tie to a URL to
provide direct access. S3 offers service level agreement.
8.1.3. Simple Queue Service (SQS)
It offers highly reliable message queue. SQS
generates delivery to messages and stores messages for
later transmission if required. SQL interconnects all of
AWS resources. Application publishes and subscribes to a
specified queue. SQS offers service level agreement.
8.1.4 Simple DB
It provides a query interface to structured textual
data. Query language and data formatting is simple.
Primary data can be associated with up to 256 attributes
or metadata. Any application can use basic Boolean
operations to query the information. This is currently in
8.1.5. Cloud Front
It provides efficient access to distributed content using
Amazon’s array of server through out the world. It
integrates with S3 that holds the original content that is
then distributed to edge latency.
To access any of the services, user must get an
account and activate the services as required. After
activation, services can be accessed through access key
User can obtain account and access key certificate free of
8.2 Google APP Engine (GAE)
This is used to develop and host web application
on Google’s web server. GAE focuses on computing
capabilities provided by Google SDK. It leverages an
agile language (Python) and will known RIA
framework (Django). Django is nothing but an open
source web application written in Python and use
model-view-controller design pattern.. GAE provides
the following features
• Persistent storage with the facility of querying,
sorting, and transaction
• Scaling and load balancing will be done
• APIs are available to authenticate the users and
sending email using Google account
• It provides a full-featured development
environment that simulates the original Google
With all the facilities, there are some limitations in
• An application can only be fetched on the
internet through the provided URL, APIs
• User can connect to the application only through
HTTP or HTTPs request over a fixed port.
• Although the application can read from the file
system only when the file is uploaded with the
• The application cannot write into the file system.
• The application can only store data into the
GAE’s data store for all data that persists
between the requests.
The SDK includes all API and libraries available
on application engine. It provides a runtime
environment built on Python (2.5). It uses (Django) for
tinplating MVC architecture.
GAE supports distributed data storage for an
extremely large corpus delivered through Google’s
“Big Table” architecture. Thus improve scalability.
Google asserts BigTable has the ability to deliver high
performance interaction data in the range of several
hundred terabytes. BigTable is essentially a large flat
space that provides object relational semantics does not
really implement a full relational model.
Additional to these services GAE provides APIs to
perform following operations. GAE exposes API to
send email. User can create a mail object to send mail.
No additional setup is required for this. For
authentication, GAE provides Standard Google
A cloud application leverages the Cloud in software
architecture, often eliminating the need to install and run
the application on the customer's own computer, thus
alleviating the burden of software maintenance, ongoing
operation, and support.
A cloud client consists of computer hardware and/or
computer software which relies on The Cloud for
application delivery, or which is specifically designed for
delivery of cloud services, and which in either case is
essentially useless without it.
Cloud infrastructure, such as Infrastructure as a
service, is the delivery of computer infrastructure,
typically a platform virtualization environment, as a
A cloud platform, such as Platform as a service, the
delivery of a computing platform, and/or solution stack as
a service facilitates deployment of applications without
the cost and complexity of buying and managing the
underlying hardware and software layers.
A cloud service, such as Web Service, is “software
system[s] designed to support interoperable machine-to-
machine interaction over a network” which may be
accessed by other cloud computing components, software,
e.g., Software plus services, or end users directly.
Cloud storage involves the delivery of data storage
as a service, including database-like services, often billed
on a utility computing basis, e.g., per gigabyte per month.
10. Service Types in Cloud Computing
This picture is very basic but shows different types of
companies leveraging the cloud model. We can also see
that some types of computing are a subset of the cloud.
Let's talk about the different types and what they
represent.Early adapters saw the opportunity to reduce
costs by moving brick and mortar operations to the
Internet and increase revenue by providing services and
Figure 6. Service providers and Service types
10.1. Levels of Cloud Computing
Figure 7. A high level view of different types of
Figure 8. Connection between SAAS, PAAS, IAAS
10.1.1. SAAS (Software as a Service)
Figure 9. Software and services running at a
In the software-as-a-service cloud model, the
vendor supplies the hardware infrastructure, the software
product and interacts with the user through a front-end
portal. Services can be anything from Web-based email to
inventory control and database processing. This type of
cloud computing delivers a single application through the
browser to thousands of customers using a multitenant
architecture.Salesforce.com is by far the best-known
example among enterprise applications
10.1.2. PAAS(Platform as a Service)
These form of cloud computing delivers development
environments as a service. We build our own applications
that run on the provider's infrastructure and are delivered
to our users via the Internet from the provider's servers.
Figure 10. Infrastructure on a specified development
platform hosted externally
Platform-as-a-service in the cloud is defined as a
set of software and product development tools hosted on
the provider's infrastructure Developers create
applications on the provider's platform over the
Internet.PaaS providers may use APIs, website portals or
gateway software installed on the customer's computer.
Prime examples include Salesforce.com's Force.com,
Coghead and the new Google App Engine PaaS providers
like Google's App Engine and Force.com allows to build
our own applications on top of virtual server instances but
restrict us to use their development languages.
10.1.3. IAAS (Infrastructure as a Service)
Infrastructure-as-a-Service like Amazon Web
Services provides virtual server instances with unique IP
addresses and blocks of storage on demand. Customers
use the provider's application program interface (API) to
start, stop, access and configure their virtual servers and
storage. Allows a company to pay for only as much
capacity as is needed, and bring more online as soon as
required. VMware DRS (Distributed Resource Scheduler)
intelligently allocate available resources among virtual
machines according to business needs. The most popular
IaaS vendor is Amazon.
Figure 11. Infrastructure hosted externally without
"In the Cloud" means leveraging infrastructure off-
premise.With SaaS solutions,the underlying infrastructure
is hidden.With PaaS, manage the amount of virtual server
instances we use but we must use the technologies
required by the provider. With IaaS, we manage the
resources we use and are free to leverage whatever
technologies we choose to deploy on.
10.1.4. Web Services in the Cloud
Closely related to SaaS, Web service providers offer
APIs that enable developers to exploit functionality over
the Internet, rather than delivering full-blown
10.1.5. MSP(Managed Service providers)
One of the oldest forms of cloud computing, a
managed service is basically an application exposed to IT
rather than to end-users, such as a virus scanning service
for e-mail or an application monitoring service (which
Mercury, among others, provides).
10.1.6. Service commerce platforms
A hybrid of SaaS and MSP, this cloud computing
service offers a service hub that users interact with.
They're most common in trading environments, such as
expense management systems that allow users to order
travel or secretarial services from a common platform that
then coordinates the service delivery and pricing within
the specifications set by the user. Well-known examples
include Rearden Commerce and Ariba.
10.1.7. Internet Integration
The integration of cloud-based services is in its
early days. OpSource, which mainly concerns itself with
serving SaaS providers, recently introduced the OpSource
Services Bus, which employs in-the-cloud integration
technology from a little startup called Boomi.
SaaS provider Workday recently acquired another
player in this space, CapeClear, an ESB (enterprise
service bus) provider that was edging toward b-to-b
integration. Way ahead of its time, Grand Central --
which wanted to be a universal "bus in the cloud" to
connect SaaS providers and provide integrated solutions
to customers -- flamed out in 2005.
Figure 12. Internet
12. Cloud Computing Applications
The applications of cloud computing are practically
limitless. With the right middleware, a cloud computing
system could execute all the programs a normal computer
could run. Potentially, everything from generic word
processing software to customized computer programs
designed for a specific company could work on a cloud
computing system. Why would anyone want to rely on
another computer system to run programs and store
data? Here are just a few reasons:
Clients would be able to access their applications and
data from anywhere at any time. They could access
the cloud computing system using any computer
linked to the Internet. Data wouldn't be confined to a
hard drive on one user's computer or even a
corporation's internal network.
It could bring hardware costs down. Cloud
computing systems would reduce the need for
advanced hardware on the client side. User wouldn’t
need to buy the fastest computer with the most
memory, because the cloud system would take care
of those needs for the user. Instead, the user could
buy an inexpensive computer terminal. The terminal
could include a monitor, input devices like a
keyboard and mouse and just enough processing
power to run the middleware necessary to connect to
the cloud system. You wouldn't need a large hard
drive because you'd store all your information on a
Corporations that rely on computers have to make
sure they have the right software in place to achieve
goals. Cloud computing systems give these
organizations company-wide access to computer
applications. The companies don't have to buy a set
of software or software licenses for every employee.
Instead, the company could pay a metered fee to a
cloud computing company.
Servers and digital storage devices take up space.
Some companies rent physical space to store servers
and databases because they don't have it available on
site. Cloud computing gives these companies the
option of storing data on someone else's hardware,
removing the need for physical space on the front
Corporations might save money on IT support.
Streamlined hardware would, in theory, have fewer
problems than a network of heterogeneous machines
and operating systems.
If the cloud computing system's back end is a grid
computing system, then the client could take
advantage of the entire network's processing power.
Often, scientists and researchers work with
calculations so complex that it would take years for
individual computers to complete them. On a grid
computing system, the client could send the
calculation to the cloud for processing. The cloud
system would tap into the processing power of all
available computers on the back end, significantly
speeding up the calculation.
It is highly reliable, stable and easy to use
It reduces the capital costs and operation costs for the
It increases the Productivity and improves
Device and Location independence
Multi-tenancy, Reliability, Scalability
One of the main advantages of cloud computing are
those both small and medium sized businesses can
instantly obtain the benefits of the enormous
infrastructure without having to implement and
administer it directly. This also permits accessibility
to multiple data centers anywhere on the globe. It
also means that as the need for resources increases,
companies can add additional service as and when
needed from the cloud computing vendor without
having to pay for additional hardware.
Mobility Like most networks it allows users to
connect even without their own computers, meaning
you can do your work from anywhere in the world as
long as you have a internet connection and a
computer access. So you can take your work with
you on your wedding and vacations
No Downloads: The users do not need to download
anything, so that saves time and hard drive space for
users. They can just log onto the network.
Shared Resources A key component of cloud
computing is that companies share resources. With
cloud computing, this allows them all to have access
to the resources via cloud computing. This again
saves businesses time and money by placing their
resources all in one location that is easy for their
workers to look up and access
Cloud computing with all its benefits also has its
own set of limitations which restrict enterprises to move
their applications in the cloud. Some of these limitations
Customization is nearly impossible
Scalability problems with Sequential processing
Data privacy issues because of the common resources
Lack of high speed Internet connectivity
Reliability problems related to SLAs.
Cost surpasses traditional hosting in case of very high
Small and Medium Business groups are already
adopting Cloud Computing to save cost. Cloud computing
is the next big wave in computing. Cloud Computing
holds a lot of promise and it’s believed that it is likely to
be a major influence on hosting and application
It covers a range of IT practices that really can
benefit business. It has many benefits, such as better
hardware management, since all the computers are the
same and run the same hardware. It also provides
for better and easier management of data security, since
all the data is located on a central server, so
administrators can control who has and doesn't have
access to the files. But there are problems, and they need
to be addressed intelligently.