Virtualization in Cloud Computing and

Types
Virtualization is a technique of how to separate a service from the
underlying physical delivery of that service. It is the process of creating
a virtual version of something like computer hardware. It was initially
developed during the mainframe era. It involves using specialized
software to create a virtual or software-created version of a computing
resource rather than the actual version of the same resource. With the
help of Virtualization, multiple operating systems and applications can
run on same machine and its same hardware at the same time,
increasing the utilization and flexibility of hardware.
In other words, one of the main cost effective, hardware reducing, and
energy saving techniques used by cloud providers is virtualization.
Virtualization allows to share a single physical instance of a resource or
an application among multiple customers and organizations at one
time. It does this by assigning a logical name to a physical storage and
providing a pointer to that physical resource on demand. The term
virtualization is often synonymous with hardware virtualization, which
plays a fundamental role in efficiently delivering Infrastructure-as-a-
Service (IaaS) solutions for cloud computing. Moreover, virtualization
technologies provide a virtual environment for not only executing
applications but also for storage, memory, and networking.

The machine on which the virtual machine is going to be built is known

as Host Machine and that virtual machine is referred as a Guest
Machine.
BENEFITS OF VIRTUALIZATION
1. More flexible and efficient allocation of resources.
2. Enhance development productivity.
3. It lowers the cost of IT infrastructure.
4. Remote access and rapid scalability.
5. High availability and disaster recovery.
6. Pay peruse of the IT infrastructure on demand.
7. Enables running multiple operating systems.
Types of Virtualization:
1.Application Virtualization.
2.Network Virtualization.
3.Desktop Virtualization.
4.Storage Virtualization.
5.Server Virtualization.
6.Data virtualization.
1. Application Virtualization:
Application virtualization helps a user to have remote access of an
application from a server. The server stores all personal information
and other characteristics of the application but can still run on a local
workstation through the internet. Example of this would be a user who
needs to run two different versions of the same software. Technologies
that use application virtualization are hosted applications and
packaged applications.
2. Network Virtualization:
The ability to run multiple virtual networks with each has a separate
control and data plan. It co-exists together on top of one physical
network. It can be managed by individual parties that potentially
confidential to each other.
Network virtualization provides a facility to create and provision virtual
networks—logical switches, routers, firewalls, load balancer, Virtual
Private Network (VPN), and workload security within days or even in
weeks.
3. Desktop Virtualization:
Desktop virtualization allows the users’ OS to be remotely stored on a
server in the data centre. It allows the user to access their desktop
virtually, from any location by a different machine. Users who want
specific operating systems other than Windows Server will need to
have a virtual desktop. Main benefits of desktop virtualization are user
mobility, portability, easy management of software installation,
updates, and patches.
4. Storage Virtualization:
Storage virtualization is an array of servers that are managed by a
virtual storage system. The servers aren’t aware of exactly where their
data is stored, and instead function more like worker bees in a hive. It
makes managing storage from multiple sources to be managed and
utilized as a single repository. storage virtualization software maintains
smooth operations, consistent performance and a continuous suite of
advanced functions despite changes, break down and differences in
the underlying equipment.
5. Server Virtualization:
This is a kind of virtualization in which masking of server resources
takes place. Here, the central-server(physical server) is divided into
multiple different virtual servers by changing the identity number,
processors. So, each system can operate its own operating systems in
isolate manner. Where each sub-server knows the identity of the
central server. It causes an increase in the performance and reduces
the operating cost by the deployment of main server resources into a
sub-server resource. It’s beneficial in virtual migration, reduce energy
consumption, reduce infrastructural cost, etc.
6. Data virtualization:
This is the kind of virtualization in which the data is collected from
various sources and managed that at a single place without knowing
more about the technical information like how data is collected, stored
& formatted then arranged that data logically so that its virtual view
can be accessed by its interested people and stakeholders, and users
through the various cloud services remotely. Many big giant companies
are providing their services like Oracle, IBM, At scale, Cdata, etc.
It can be used to performing various kind of tasks such as:
 Data-integration
 Business-integration
 Service-oriented architecture data-services
 Searching organizational data

What is a virtual machine?

 A virtual machine (VM) is a tightly isolated software container that can run operating
systems and applications as if it were a physical computer. Although there is no hardware
required for a virtual machine to operate, it still contains a CPU, RAM hard disk and
network interface card (NIC), just like a physical computer.
 VMs allow businesses to run operating systems that behave like a completely separate
computer, either in an app window or on a desktop. Common uses of VMs include
running software that requires a different operating system or to test applications in a safe
environment.
 What are the benefits of using a Virtual Machine?
 Being able to use apps and operating systems without the need for hardware presents
users with some advantages over a traditional computer. The benefits of virtual machines
include:
 1. Compatibility
 Virtual machines host their own guest operating systems and applications, using all the
components found in a physical computer (motherboard, VGA card, network card
controller, etc). This allows VMs to be fully compatible with all standard x86 operating
systems, applications and device drivers. You can therefore run all the same software that
you would usually use on a standard x86 computer.
 2. Isolation
 VMs share the physical resources of a computer, yet remain isolated from one another.
This separation is the core reason why virtual machines create a more secure environment
for running applications when compared to a non-virtual system. If, for example, you’re
running four VMs on a server and one of them crashes, the remaining three will remain
unaffected and will still be operational.
 3. Encapsulation
 A virtual machine acts as a single software package that encapsulates a complete set of
hardware resources, an operating system, and all its applications. This makes VMs
incredibly portable and easy to manage. You can move and copy a VM from one location
to another like any other software file, or save it on any storage medium — from storage
area networks (SANs) to a common USB flash drive.
 4. Hardware independence
 Virtual machines can be configured with virtual components that are completely
independent of the physical components of the underlying hardware. VMs that reside on
the same server can even run different types of operating systems. Hardware
independence allows you to move virtual machines from one x86 computer to another
without needing to make any changes to the device drivers, operating system or
applications.
 What Types of Virtualization are there?
 Virtual machines allow you to virtualise all the traditional components of data centres or
IT infrastructure. The five core types of virtualisation include:
 Hardware virtualisation
 Hardware virtualisation, sometimes known as server virtualisation, allows hardware
resources to be used more efficiently. With virtualisation, a single machine can run
multiple different operating systems simultaneously.
 Software virtualisation
 With software virtualisation, we can create a computer system featuring hardware that
allows one or more guest operating systems to run on a physical host machine. You can
also virtualise applications and deliver them from a server to an end user’s device,
allowing employees to access centrally hosted applications when working remotely.
 Storage virtualisation
 By consolidating multiple physical storage devices to appear as one, storage virtualisation
can increase performance speed, improve load balancing, and reduce costs. It’s also
useful for disaster recovery planning, as virtual storage data can be duplicated and
transferred quickly to another location, helping to reduce downtime.
 Network virtualisation
 Network virtualisation combines equipment into a single software-based virtual network,
creating multiple sub-networks on the same physical network. It allows available
bandwidth to be divided into multiple, independent channels, each of which can be
assigned to servers and devices in real-time. Businesses can enjoy the advantages of
increased reliability, network speed, security and improved monitoring of data usage.
 Desktop virtualisation
 Desktop virtualisation is one of the most common types of virtualisation. It separates the
desktop environment from the hardware of a computer onto a remote server. Users will
benefit from easy accessibility, better data security, ease of management and the cost
savings of software licences and updates.
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 Hypervisor Comparison: KVM, Xen, VMware, Hyper-V

 There are many considerations when selecting a hypervisor such as the
performance, how mature the technology is, how it integrates with existing systems,
the commercial implications and guest and functionality support. In our latest white
paper, we put together a guide that sets out to help you select the most appropriate
hypervisor.
 Within the paper, we compared four major hypervisors – KVM, Xen, VMware and
Hyper-V. Here is a snapshot of the hypervisors we reviewed and a bit about each:



 KVM – a Linux based open source hypervisor. First introduced into the Linux kernel
in February 2007, it is now a mature hypervisor and is probably the most widely
deployed open source hypervisor in an open source environment. KVM is used in
products such as Redhat Enterprise Virtualization (RHEV).


 Xen – An open source hypervisor which originated in a 2003

Cambridge University research project. It runs on Linux (though being a Type 1
hypervisor, more properly one might say that its dom0 host runs on Linux, which in
turn runs on Xen). It was originally supported by XenSource Inc, which was acquired
by Citrix Inc in 2007.


 VMware – is not a hypervisor, but the name of a company,

VMware Inc. Our experience with VMware involves its vSphere product. vSphere
uses VMware’s ESXi hypervisor. VMware’s hypervisor is very mature and extremely
stable.


 Hyper-V – Hyper-V is a commercial hypervisor provided by Microsoft. Whilst
excellent for running Windows, being a hypervisor it will run any operating system
supported by the hardware platform.