UNIT-I

Introduction of Cloud Computing

 Cloud computing is the delivery of computing services—servers, storage, databases,
networking, software, analytics, intelligence and more—over the Internet.
 (“The cloud”) to offer faster innovation, flexible resources and economies of scale. You
typically pay only for cloud services you use, helping lower your operating costs, run
your infrastructure more efficiently and scale as your business needs change.

Cloud overview architecture

Evolution of cloud computing

 Cloud computing means different to different people, its benefits are different to different
organization and people.
 To IT managers, it means to minimize cap-ex by outsourcing most of the hardware and
software resources.
 To ISVs, it means to reach out to more users by offering a SaaS solution. To end users, it
means to access an application from anywhere using any device.
 The following diagram illustrates a high level overview.
  Cloud computing applications in the beginning of the computing era, the relationship
between the user and the machine was one-to-one.
 One user used to access the applications that (s) he needs to use on one machine. Then
came the Internet era. In the Internet era, the relationship between the user and the
machine was many-to-one.
 Many users could access applications running on one machine. The applications in this
case were websites or client-server applications, the machine was a central server hosting
the server application, web server or/and the database.
 In cloud computing, the relationship between the user and machine are many-to-
many. Many users can access an application that is served from many machines.
 Now, what was the reason of this evolution? What were the driving factors behind this?
The reason for the evolution from PC-based application to Internet-based
application was obvious.

NEED FOR CLOUD COMPUTING

 Clouds can provide users with a number of different benefits.
Many businesses large and small use cloud computing today either directly (e.g. Google
or Amazon) or indirectly (e.g. Twitter) instead of traditional on-site alternatives. There
are a number of reasons why cloud computing is so widely used among businesses today.
 Reduction of costs – unlike on-site hosting the price of deploying applications in the
cloud can be less due to lower hardware costs from more effective use of physical
resources.
 Universal access - cloud computing can allow remotely located employees to access
applications and work via the internet.
 Up to date software - a cloud provider will also be able to upgrade software keeping in
mind feedback from previous software releases.
 Choice of applications. This allows flexibility for cloud users to experiment and choose
the best option for their needs. Cloud computing also allows a business to use, access and
pay only for what they use, with a fast implementation time
 Potential to be greener and more economical - the average amount of energy needed
for a computational action carried out in the cloud is far less than the average amount for
an on-site deployment. This is because different organizations can share the same
physical resources securely, leading to more efficient use of the shared resources.
 Flexibility – cloud computing allows users to switch applications easily and rapidly,
using the one that suits their needs best. However, migrating data between applications
can be an issue.

Top benefits of cloud computing

Cloud computing is a big shift from the traditional way businesses thinking about IT
resources. Here are seven common reasons organizations are turning to cloud computing
services:

 Cost
 Cloud computing eliminates the capital expense of buying hardware and software
and setting up and running on-site datacenters—the racks of servers, the round-
the-clock electricity for power and cooling, the IT experts for managing the
infrastructure. It adds up fast.

 Speed
 Most cloud computing services are provided self service and on demand, so even
vast amounts of computing resources can be provisioned in minutes, typically
with just a few mouse clicks, giving businesses a lot of flexibility and taking the
pressure off capacity planning.
 Global scale
 The benefits of cloud computing services include the ability to scale elastically.
 In cloud speak, that means delivering the right amount of IT resources
 For example, more or less computing power, storage, bandwidth—right when it is
needed and from the right geographic location.
 Productivity
 On-site datacenters typically require a lot of “racking and stacking”—hardware set
up, software patching and other time-consuming IT management chores.
 Cloud computing removes the need for many of these tasks, so IT teams can spend
time on achieving more important business goals.
 Performance
 The biggest cloud computing services run on a worldwide network of secure
datacenters, which are regularly upgraded to the latest generation of fast and
efficient computing hardware.
 This offers several benefits over a single corporate datacenter, including reduced
network latency for applications and greater economies of scale.
  Security
 Many cloud providers offer a broad set of policies, technologies and controls that
strengthen your security posture overall, helping protect your data, apps and
infrastructure from potential threats.

Cloud services

Limitations of Cloud Computing

If there is a problem in data center, all virtual machines are affected. There might or
might not be a backup of the data if an enterprise relies only on the cloud for its data
management needs.
1. Network connection
 The concept assumes that the client has reliable network connection.
 If there are problems of network connectivity, accessing the cloud also
becomes a problem.
 Performance of the cloud applications also depend on the performance of
network at clients’ side.
 Upload and download speeds are slower as compared to that of a local server.

2. Control of data security

 In a public cloud, the client does not have the control over security of his/ her own
data.
 The clients’ data can be susceptible to hacking or phishing attacks.
 Since the servers on cloud are interconnected it is easy for malware to spread.
3. Additional costs

 Although cloud computing offers cost benefits, it has some hidden or additional
costs as well.
 Clients are charged extra for data transfer or other services.
 Initial offerings are priced higher, till economies of scale work out for the service
provider.

4. Peripherals
 Peripheral devices like printers or scanners might not work with cloud.
 Many of them require software to be installed locally. Networked peripherals
have lesser problems.

5. Integration

 Integrating internal applications with those on cloud can be complex and in some
cases not viable.

6. Generic

 Public cloud offerings are very generic and offer multi-tenancy service which all
organizations might not be comfortable with.
 Implementing an in-house cloud is more complex to implement and are
burdensome on internal resources if the organization is not large enough.
 Cloud service providers are continuously evolving solutions to overcome the
above mentioned hurdles.
 Some enterprises are seeing clear benefits in shifting to the cloud and are
adopting it.

BASICS OF VIRTUALIZATION

Virtualization is a technique, which allows to share single physical instance of an application or

resource among multiple organizations or tenants (customers). It does so by assigning a logical
name to a physical resource and providing a pointer to that physical resource on demand.

Virtualization Concept

Creating a virtual machine over existing operating system and hardware is referred as Hardware
Virtualization. Virtual Machines provide an environment that is logically separated from the
underlying hardware.

The machine on which the virtual machine is created is known as host machine and virtual
machine is referred as a guest machine. This virtual machine is managed by a software or
firmware, which is known as hypervisor.

Hypervisor
The hypervisor is a firmware or low-level program that acts as a Virtual Machine Manager.
There are two types of hypervisor:

Type 1 hypervisor executes on bare system. LynxSecure, RTS Hypervisor, Oracle VM, Sun
xVM Server, VirtualLogic VLX are examples of Type 1 hypervisor. The following diagram
shows the Type 1 hypervisor.

Type1 Hypervisor

The type1 hypervisor does not have any host operating system because they are installed on a
bare system.

Type 2 hypervisor is a software interface that emulates the devices with which a system
normally interacts. Containers, KVM, Microsoft Hyper V, VMWare Fusion, Virtual Server 2005
R2, Windows Virtual PC and VMWare workstation 6.0 are examples of Type 2 hypervisor. The
following diagram shows the Type 2 hypervisor.

Type2 Hypervisor
Types of virtualization

1. Hardware/server virtualization
2. Network virtualization
3. Storage virtualization
4. Memory virtualization
5. Software virtualization
6. Data virtualization
7. Desktop virtualization

DESKTOP VIRTUALIZATION

Desktop virtualization is the concept of isolating a logical operating system (OS) instance from
the client that is used to access it.

There are several different conceptual models of desktop virtualization, which can broadly be
divided into two categories based on whether or not the operating system instance is executed
locally or remotely. It is important to note that not all forms of desktop virtualization involve the
use of virtual machines (VMs).
Host-based forms of desktop virtualization require that users view and interact with their
desktops over a network by using a remote display protocol. Because processing takes place in a
data center, client devices can be thin clients, zero clients, smartphones, and tablets. Included in
this category are:

Host-based virtual machines: Each user connects to an individual virtual machine that is hosted
in a data center. The user may connect to the same VM every time, allowing personalization,
(known as a persistent desktop) or be given a random VM from a pool (a non-persistent
desktop). See also: virtual desktop infrastructure (VDI)

Shared hosted: Users connect to either a shared desktop or simply individual applications that
run on a server. Shared hosted is also known as remote desktop services or terminal services.
See also: remote desktop services and terminal services.

Host-based physical machines or blades: The operating system runs directly on physical
hardware located in a data center.

Client-based types of desktop virtualization require processing to occur on local hardware; the
use of thin clients, zero clients, and mobile devices is not possible. These types of desktop
virtualization include:

OS streaming: The operating system runs on local hardware, but boots to a remote disk image
across the network. This is useful for groups of desktops that use the same disk image. OS
streaming requires a constant network connection in order to function; local hardware consists of
a fat-client with all of the features of a full desktop computer except for a hard drive.

Client-based virtual machines: A virtual machine runs on a fully-functional PC, with a

hypervisor in place. Client-based virtual machines can be managed by regularly syncing the disk
image with a server, but a constant network connection is not necessary in order for them to
function.

CASE STUDY

VMWare

VM, which stands for "Virtual Machine" (not to be confused with the broader term virtual
machine), is a widely-installed operating system for IBM-compatible computers and servers that
can host other operating systems in such a way that each operating system behaves as if it were
installed on a self-contained computer with its own set of programs and hardware resources

VMware is a virtualization and cloud computing software provider for x86-compatible

computers.

VMware Inc. is a subsidiary of EMC Corporation and has its headquarters in Palo Alto,
California.

VMware virtualization is based on the ESX/ESXi bare metal hypervisor, supporting virtual
machines.

The term "VMware" is often used in reference to specific VMware Inc. products such as
VMware Workstation, VMware View, VMware Horizon Application Manager and VMware
vCloud Director..

VMware Products

Desktop software

 VMware Workstation This software suite allows users to run multiple instances of x86 or
x86-64 -compatible operating systems on a single physical PC.
 VMware Fusion provides similar functionality for users of the Intel Mac platform, along
with full compatibility with virtual machines created by other VMware products.
 VMware Player is for users without a license to use VMware Workstation or VMware
Fusion. VMware offers this software as a freeware product for personal use.

Server software: VMware markets two virtualization products for servers:

 VMware ESX is an enterprise-level product, can deliver greater performance than the
freeware VMware Server, due to lower system overhead.
 VMotion and storage VMotion – VMotion is the capability to move a running virtual
machine from one ESX host to another and faster than some other editions and
Storage VMotion - the capability to move a running virtual machine from one storage
device to another
 DRS - Distributed Resource Scheduler - automatic load balancing of a ESX cluster using
VMotion
 HA - High Availability - In case of hardware failure in a cluster, the virtual servers will
automatically restart on another host in the cluster
 VMware ESXi is quite similar to ESX, but differentiates in that the Service Console is
removed, and replaced with a minimal BusyBox installation.