UNIT-I

Cloud Computing in a Nutshell

Cloud Computing
Cloud computing is a general term for anything that involves delivering hosted
services over the Internet.
“Cloud computing is the use of computing resources (hardware and software)
that are delivered as a service over a network (typically the Internet). The name
comes from the common use of a cloud-shaped symbol as an abstraction for the
complex infrastructure it contains in system diagrams. Cloud computing entrusts
remote services with a user's data, software and computation.”

Cloud Benefits
 Pay as you go
 Focus on business rather than IT
 Elasticity - Scale up and down based on business need

Cloud Models
 Deployment Models: Public Cloud, Private Cloud, Hybrid Cloud,
Community Cloud
 Service Models: SaaS, PaaS, IaaS

Essential Characteristics
 On Demand Self-Service: Allows for provisioning of computing
resources automatically as needed.
 Broad Network Access: Access to cloud resources is over the network
using standard mechanisms provided through multi-channels.
 Resource Pooling: The vendors9 resources are capable of being pooled to
serve multiple clients using a multi-tenant model, with different physical
and virtual resources in a dynamic way.
 Example of resources include; computation capabilities, storage and
memory.
 Rapid Elasticity: Allows for rapid capability provisioning, for quick
scaling out and scaling in of capabilities. The capability available for
provisioning to the client seems to be unlimited and that it can be
purchased as demanded.

 Measured Service: Allows monitoring, control and reporting of usage. It

also allows for transparent between the provider and the client.

LAYERS AND TYPES OF CLOUDS

Cloud computing
Cloud computing is defined as delivery of hostel services over the internet in a
one demand model. A could provider offer resources as service over the
internet that can be consumed on a pay-as-you-use basis.

Layers or services of cloud

 Software as service
 Platform as a service
 Infrastructure as a service

Software as a service (SaaS)

“Software as a service is the hosted delivery of software that consumers can
access over the internet.” This definition is rather simplistic.
Two features of a SaaS application are scalability and configurability.
In mature SaaS application, the customer should be able to customize their
instance of the software using meta data. Depending on who you talk to multi-
tenancy is yet another feature of SaaS applications. Multiple customers share a
single instance of the software and the provider can optimize the resources to
suit individual demands.
Google Apps - a SaaS version of desktop applications where the software is
hosted on google9s servers. Salesforce - SaaS CRM products.

Platform Cloud – Platform as a service

It offers a complete platform and the tools to develop and deploy applications
on the platforms.
Typically, the PaaS vender also provide tools and the other services that enable
raped applications development.
Application developed on the platform has its own development model and
developers need to be aware of these.
App Engine is a PaaS offering from Google. Applications are developed and
deployed on Google9s infrastructure. Google App Engine uses big table to store
data. This is an example of platform specific development, a change that
traditional developers will have to face when they move to App Engine. It does
not support relational databases.

Force.com is a PaaS offering from Salesforce. Developers can create

applications that run on the force.com platform. It includes database, workflow
and UI tools. Applications can be built using their proprietary Apex
programming language or using Visual Force (a tag-based markup language).
Microsoft Azure is Microsoft9s platform as a service offering. It includes an
OS with .NET runtime, a database (SQL Azure) and other services that make it
easier to couple on-premise and off-premise applications.

Infrastructure Cloud – Infrastructure as a service (IaaS)

Infrastructure as a Service is the hosted delivery of infrastructure services such

as servers, networks and other hardware to consumers. IaaS provides
consumers
access to on-demand, scalable storage and compute power.
Amazon EC2 is an example of IaaS which provides scalable compute capacity
in the cloud. Basically, consumers get a machine that they customize and use.
This is an example of hardware as a service.

A different way to think about the different layers of cloud computing is to

think in terms of control that the customer has has:
 With SaaS you use the application with little customization.
 With PaaS you create applications that run on the platform. You are
limited by the platform as to what applications you can create.
 With IaaS you build applications without any tie in to the platform.

Types Of Cloud
Cloud computing is usually described in one of two ways. Either based on the
cloud location, or on the service that the cloud is offering.
Based on a cloud location, we can classify cloud as:
 Public
 Private
 Hybrid
 Community cloud

Based on a service that the cloud is offering; we are speaking of either:

 IaaS (Infrastructure-as-a-Service)
 PaaS (Platform-as-a-Service)
 SaaS (Software-as-a-Service)
 or, Storage, Database, Information, Process, Application, Integration,
Security, Management, Testing-as-a-service

When we talk about public cloud, we mean that the whole computing
infrastructure is located on the premises of a cloud computing company that
offers the cloud service. The location remains, thus, separate from the
customer
and he has no physical control over the infrastructure.
As public clouds use shared resources, they do excel mostly in performance,
but
are also most vulnerable to various attacks.
Private cloud means using a cloud infrastructure (network) solely by one
customer/organization. It is not shared with others, yet it is remotely located. If
the cloud is externally hosted. The companies have an option of choosing an
on-
premise private cloud as well, which is more expensive, but they do have a
physical control over the infrastructure.
The security and control level are highest while using a private network. Yet,
the
cost reduction can be minimal, if the company needs to invest in an on-premise
cloud infrastructure.
Hybrid cloud, of course, means, using both private and public clouds,
depending on their purpose.
For example, public cloud can be used to interact with customers, while
keeping
their data secured through a private cloud.
Community cloud implies an infrastructure that is shared between
organizations, usually with the shared data and data management concerns.
For example, a community cloud can belong to a government of a single
country. Community clouds can be located both on and off the premises

Cloud services
The most popular services of the cloud are infrastructure, platform, software, or
storage.
The most common cloud service is that one offering data storage disks and
virtual servers, i.e. infrastructure. Examples of Infrastructure-as-a-Service (IaaS)
companies are Amazon, Rackspace, Flex scale
If the cloud offers a development platform, and this includes operating system,
programming language execution environment, database, and web server, the
model is known as Platform-as-a-Service (PaaS), examples of which are Google
App Engine, Microsoft Azure, Salesforce. Operating system can be frequently
upgraded and developed with PaaS, services can be obtained from diverse
sources, and programming can be worked in teams (geographically distributed)

Public cloud
public cloud is basically the internet. Service providers use the internet to
make resources, such as applications (also known as Software-as-a-service) and
storage, available to the general public, or on a public cloud.
Examples of public clouds include Amazon Elastic Compute Cloud (EC2), IBM9s
Blue Cloud, Sun Cloud, Google Apennine and Windows Azure Services Platform.
For users, these types of clouds will provide the best economies of scale, are
inexpensive to set-up because hardware, application and bandwidth costs are
covered by the provider. It9s a pay-per-usage model and the only costs incurred
are based on the capacity that is used.
There are some limitations, however; the public cloud may not be the right fit
for every organization. The model can limit configuration, security, and SLA
specificity, making it less-than-ideal for services using sensitive data that is
subject to compliancy regulations

Private Clouds
Private clouds are data centre architectures owned by a single company that
provides flexibility, scalability, provisioning, automation and monitoring. The
goal of a private cloud is not sold <as-a-service= offerings to external customers
but instead to gain the benefits of cloud architecture without giving up the
control of maintaining your own data centre.
Private clouds can be expensive with typically modest economies of scale. This
is usually not an option for the average Small-to-Medium sized business and is
most typically put to use by large enterprises. Private clouds are driven by
concerns around security and compliance, and keeping assets within the
firewall.
Hybrid Clouds
By using a Hybrid approach, companies can maintain control of an internally
managed private cloud while relying on the public cloud as needed. For
instance during peak periods individual applications, or portions of applications
can be migrated to the Public Cloud. This will also be beneficial during
predictable outages: hurricane warnings, scheduled maintenance windows,
rolling brown/blackouts.
The ability to maintain an off-premise disaster recovery site for most
organizations are impossible due to cost. While there are lower cost solutions
and
alternatives the lower down the spectrum an organization gets, the capability to
recover data quickly reduces. Cloud based Disaster Recovery (DR)/Business
Continuity (BC) services allow organizations to contract failover out to a
Managed Services Provider that maintains multi-tenant infrastructure for
DR/BC, and specializes in getting business back online quickly

Desired feature of cloud

Key features of cloud computing
The most talked-about term currently in the IT industry is cloud computing.
Everyone is thinking about cloud computing from different perspectives.
Some emphasize the cost benefits associated with it, while others are still
cautious about security and privacy. It has become extremely important to
understand the key defining features of cloud computing.
1. Resource pooling and Elasticity
In cloud computing, resources are pooled to serve a large number of
customers. Cloud computing uses multi-tenancy where different resources
are dynamically allocated and de-allocated according to demand. From the
user9s end, it is not possible to know where the resource actually resides.
The resource allocation should be elastic, in the sense that it should change
appropriately and quickly with the demand. If on a particular day the
demand increases several times, then the system should be elastic enough to
meet that additional need, and should return to the normal level when the
demand decrease.
2. Self service and on demand service
Cloud computing is based on self-service and on-demand service models. It
should allow the user to interact with the cloud to perform tasks like
building, deploying, managing, and scheduling. The user should be able to
access computing capabilities as and when they are needed and without any
interaction from the cloud-service provider. This would help users to be in
control, bringing agility in their work, and to make better decisions on the
current and future needs.
3. Pricings or Per-usage Metering and Billing.
It is completely based on usage. The user is billed based on the number of
resources they use. This helps the user to track their usage and ultimately
help to reduce cost. Cloud computing must provide means to capture,
monitor, and control usage information for accurate billing. The
information gathered should be transparent and readily available to the
customer.

67. Quality of Service or Customization

Cloud computing must assure the best service level for users. Services
outlined in the service-level agreements must include guarantees on
round-the-clock availability, adequate resources, performance, and
bandwidth. Any compromise on these guarantees could prove fatal for
customers

The decision to switch to cloud computing should not be based on the hype
in the industry. A good understanding of the technology enables the user to
make smarter decisions. Knowing all the features will empower the
business users to understand and negotiate with the service providers in a
proactive manner.

Challenges and risk

Security & Privacy
Security is a great concern for CIOs when moving their data to the cloud.
Although security in the cloud is generally reliable and proficient, CIOs need to
that cloud provider they choose to work with has fully secure cloud
environment.
CIOs are becoming more reluctant to hand over important data to a third party
provider. With the growth in data breaches and the potential financial penalties
and loss of reputation for companies who fall victim, moving your private data
to an external provider is more daunting than ever.
A well-established cloud computing vendor will ensure they have the latest
sophisticated security systems in place to defend against threats. We have put
together a list of questions below that you should ask a cloud provider.
 Where does your data reside?
 Is the data encrypted?
 How do move your data from cloud?
 What are your security governance policies and procedures?

Service quality
Service quality is often one of the most significant factors that businesses cite a
reason for not moving their business applications to the cloud. Often
businesses feel as though the SLAs provided by the cloud providers today are
not adequate to assure the requirements for running a production application
on the cloud, especially those related to availability, performance and
scalability.
According to a recent survey 43% of IT decision makers are planning to invest
more into cloud computing this year. CIOs need assurance that the company9s
data will be secure and available, and the service reliable at all times. Ensuring
maximum upkeep of the service is paramount for the profitability and
sustainability of the business. We9ve put together a list of ten questions you
should ask a provider before signing the contract:
1. What are your minimum service levels?
2. What remedies are in place when a failure occurs?
3. What disaster recovery and business continuity procedures are in place?
4. How portable is my data?
5. What is your change management process?
6. What are your infrastructure and security standards?
7. How quickly do you identify and solve problems?
8. What is your escalation process?
9. What is your exit strategy?
10. What is your termination process?

Downtown and accessibility

Service quality doesn9t have to be compromised when your data is in the cloud.
Accessing your data when you need it is a basic requirement from many
organisations. The challenge with the cloud is that the data is accessed via an
internet connection rather than a local connection. So, when the network or
internet connection is down, it also means that cloud services are also down;
thus, data cannot be accessed.
Access to data
cloud-based servers do not always have the most effective or appropriate customer service
support systems. CIOs often express their concerns around data ownership and losing control
of their data when moving to the cloud, but this shouldn9t be an issue. Selecting where and
how your data is stored is an important element within the decision-making process.
Integration is a problem for many organisations. Ensuring that all of the applications are able
to seamlessly integrate with one another is also a common challenge.
Important questions you should ask a cloud provider;
 How much control do I have over my data and server?

 How much time does it take to back up my data to the cloud?

 How long does it take to back up my data?
 Where does my data reside?
 How does the service provider secure my data?

 What are their audit procedures?

 What happens in the event of data corruption?

 How can I extract my data if I need to move elsewhere?

Transaction to the cloud

Many cloud adoption challenges are unknown due to the fact that cloud technology is still in
its relative infancy. CIOs are challenged deciding on the best way to transition to the cloud
and finding a cloud solution that meets the aims of the businesses, whilst improving
efficiencies.
Although transitioning to the cloud is a complex and involved process, there isn’t one route to
success. CIOs must ensure that the proposed solution compliments their business model.
There are various ways businesses can transition to the cloud. Whether it9s via private, public
or hybrid technologies, identifying the right service model for your business is a vital step.
Questions that a cloud provider should ask you;

 What are your demand patterns?

 When do you get the biggest influx of data?

 How much do you expect your data to grow?

 Do you need control over the region (geographic) where your data
resides?
 What is your SLA expectation?
Migrating data poses a number of risks for organisations if not handled
correctly. Developing a data migration strategy that integrates seamlessly with
the current IT infrastructure is key to overall success.
CIOs are challenged with finding the right service model for their business.
Finding a provider that will allow you to create a customised computing
environment is vital.
The first step in transitioning to the cloud is being able to identify the
challenges
and working with your chosen cloud provider to navigate around these barriers
in order to facilitate a successful cloud environment for the business. Whether
Public, Private or Hybrid, making sure you ask the right questions and
understand the risks for your business is imperative