2. Why Cloud Computing ?
With the advent of the cloud, an organization can try
out a new application or even develop a new
application without first investing in hardware,
software, and networking.
This can have a positive impact on companies that
want to innovate and experiment without risk.
4. As we started our discussion about cloud computing
we ran into the repetitive use of the adjective clause
as a service.
For example, Infrastructure as a Service, Hardware as
a Service, Applications as a Service, Software as a
Service, and so on.
Services you purchase from these cloud service
providers will be offered to you in a way that is similar
to your television cable provider.
6. Infrastructure as a Service (IaaS) is the delivery of a
compute foundation (servers, networking
technology, storage, and data center space) as a
service. It also includes the delivery of operating
systems and virtualization technology to manage the
7. Visualize a scenario where the hardware and the Operating
System (OS) are exposed as a Web Service over the public
Internet. Based on the principles of Web Services, we could
send a request to this service along with a few parameters.
Since the OS is expected to act as an interface to the CPU
and the devices, we can potentially invoke a service that
accepts a ‘job’ that will be processed by the OS and the
underlying hardware. Technically, this Web Service has just
turned the OS + H/W combination into a ‘Service’.
8. All that the Cloud OS offers is the infrastructure services.
You may choose to use REST API to manage this OS or use
SSH or Remote Desktop console. Technically, when you are
able to delegate a program to execute on a remote OS
running on the Web, you are leveraging Infrastructure as a
This is different from classic web hosting. Web hosting only
hosts web pages and cannot execute code that needs low
level access to the OS API. Web hosting cannot dynamically
scale on demand.
9. IaaS enables you to run your computing task on
virtually unlimited number of machines.
Remember that through IaaS, you have just moved a
server running in your backyard into the Cloud.
You pretty much own the managing, patching,
securing and the health of the remote servers.
Amazon EC2 is an example of commercial IaaS
11. With Platform as a Service (PaaS) the provider
delivers more than infrastructure. It delivers what you
can think of as a solution stack for both a software
development and runtime environment.
Platform as a Service or PaaS goes one level above
the Cloud OS.
Through this, developers can leverage a scalable
platform to run their applications.
12. Developers always develop and deploy their applications
on the application development platforms. Some of the
most popular application development platforms are .NET
In the last scenario, we have seen how the OS + H/W
combination is offered as a service. Now, imagine a
scenario where the application development platform is
offered to you as a service.
Through this, you will be able to develop and test your
applications on a low end, inexpensive notebook PC but
will able to ‘submit’ my code to run on the most powerful
13. Examples of Platform as a Service include the Google
AppEngine, Windows Azure, AppJet, Etelos, Qrimp,
and Force.com, which is the official development
environment for Salesforce.com
The advantage of PaaS is that the developers need
not worry about installing, maintaining, securing and
patching the server.
15. This layer we refer to the situation where the service
provider offers the customer the ability to run business
applications that are hosted by the provider.
Today, most of the traditional desktop applications like
word processors and spreadsheet packages are available
over the web. These new breed of applications just need a
browser and offer high fidelity with the desktop software.
This fundamentally changes the way software is deployed
16. You need not double click setup.exe to install an
Office suite on your desktop.
Just subscribe to the applications and the features
that you need and only pay for what you use.
This is almost equivalent to exposing the application
as a service.
These applications may be called as Cloud
17. Software as a Service (SaaS) is a silent revolution in
the world of traditional software products.
Consumers can now use inexpensive devices that are
capable of connecting to the web to get their work
This reduces the upfront investment in software and
brings the Pay-as-you-go model. Google Apps,
Salesforce.com and Microsoft Online Services are
examples of SaaS.
18. For IT Professionals, Cloud Computing is all about
consolidation and outsourcing the infrastructure. They are
typically focused on the Infrastructure as a Service.
Platform as a Service is an offering meant for developers
and architects. They need to design applications keeping
the statelessness of the Cloud.
If you have ever used Google Docs or Microsoft Live Mesh,
you have already leveraging the Cloud. Consumers will
subscribe to Software as a Service offerings.
20. Hosting vs. Cloud Computing
Hosting can never meet the promise of elasticity.
Even if it does, it won’t match the economics of the
Hosting does offer some level of Self Service but not
to an extent of manipulating the server.
21. Pay-By-Use attribute is emulated by some hosting
companies. But, it is not a norm in the hosting business.
Programmability is too expensive to be supported by
hosters as they cannot invest in the SDK and tools to
manage the infrastructure.
So, it is clearly evident that hosting is not the same as
23. Public Clouds
This is the most popular incarnation of the Cloud.
Many businesses and individuals realize Cloud
through the Public Cloud implementation.
It needs a huge investment and only well established
companies with deep pockets like Microsoft, Amazon
and Google can afford to set them up.
24. For example, a London based business can choose to
deploy their app at the Europe data center and an
American company prefers a data center in North America.
With the geographical spread, Public Clouds like Amazon
Web Services and Microsoft Windows Azure also offer
Content Delivery Network (CDN) features.
Through this, static content will be automatically replicated
across all the data centers around the globe thus
increasing the scalability and availability of the
25. Private Cloud
Private Clouds are normal data centers within an
enterprise with all the 4 attributes of the Cloud – Elasticity,
Self Service, Pay-By-Use and Programmability.
By setting up a Private Cloud, enterprises can consolidate
their IT infrastructure. They will need fewer IT staff to
manage the data center. They will also realize reduced
power bills because of the low electricity consumption and
lesser cooling equipment needs.
Private Cloud empowers employees within an organization
through Self Service of their IT needs. It becomes easy to
provision new machines and quickly assign them to project
26. Private Cloud borrows some of the best practices of
Public Cloud but limited to an organizational
Private Cloud can be setup using a variety of offerings
from vmWare, Microsoft, IBM, SUN and others. There
are also some of the Open Source implementations
like Eucalyptus and Ubuntu Enterprise Cloud.
27. Hybrid Cloud
There are scenarios where you need a combination of
Private Cloud and Public Cloud.
Due to the regulations and compliance issues in few
countries, sensitive data like citizen information,
patient medical history, and financial transactions
cannot be stored in servers that physically not located
within the political boundaries of a country.
28. In some scenarios, the enterprise customers want to
get best of the both worlds by logically connecting
their Private Cloud and the Public Cloud.
Through this, they can offer seamless scalability by
moving some of the on premise and Private Cloud
based applications to the Public Cloud.
Security plays a critical role in connecting the Private
Cloud to the Public Cloud.
29. Amazon Web Services has recently announced Virtual
Private Cloud (VPC) that securely bridges Private
Cloud and Amazon Web Services.
It is almost like extending your infrastructure beyond
the organizational boundary and the firewall in a
Microsoft’s recent announcement of Windows
AppFabric brings the concept of Hybrid Cloud to
Microsoft’s future customers.
30. Community Cloud
Community Cloud is implemented when a set of
businesses have a similar requirement and share the
same context. This would be made available to a set
of select organizations.
Government of India
Reserve Bank of India
A Community Cloud Goes Beyond an organization.