Unit-I

Virtualization
 Virtualisation: Concept
 Virtualization is a tec hnique, whic h allows to share a
single physical instance of a resource or an application
among multiple customers and organizations.

 It does by assigning a logical name to a physical

storage and providing a pointer to that physical
resource when demanded.

 Virtualization in cloud computing allows you to run

multiple applications and OS on the same ser ver,
thereby providing for efficient resource utilization and
reducing costs.
Virtualization Architecture
• 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.

• The machine on which the virtual machine is going

to be build is known as Host Machine and that
virtual machine is referred as a Guest Machine.
Virtualization Architecture

• The virtualization architecture includes virtual applications and virtual

infrastructure services.

• The virtual application services help in application management, and

the virtual infrastructure services can help in infrastructure
management.Both services are integrated into the virtual data center or
operating system.
• Virtual services can be used on any platform and programming
environment. These services can be accessed from the local cloud or
external cloud. In return, cloud users must pay a monthly or annual fee
to the third party.
• A hypervisor separates the operating system from the underlying
hardware. It allows the host computer to run multiple virtual machines
simultaneously and share the same computer resources.
Why is virtualization important?
• By using virtualization, you can interact with any hardware resource with greater flexibility.
• Physical servers consume electricity, take up storage space, and need maintenance. You are often limited
by physical proximity and network design if you want to access them.
• Virtualization removes all these limitations by abstracting physical hardware functionality into software.
You can manage, maintain, and use your hardware infrastructure like an application on the web.

• Consider a company that needs servers for three functions:

Store business email securely
Run a customer-facing application
Run internal business applications
Each of these functions has different configuration requirements:
The email application requires more storage capacity and a Windows operating system.
The customer-facing application requires a Linux operating system and high processing power to handle
large volumes of website traffic.
The internal business application requires iOS and more internal memory (RAM).

To meet these requirements, the company sets up three different dedicated physical servers for each
application. The company must make a high initial investment and perform ongoing maintenance and
upgrades for one machine at a time. The company also cannot optimize its computing capacity. It pays
100% of the servers’ maintenance costs but uses only a fraction of their storage and processing capacities.
 Hypervisor
5
 The hypervisor is a softwre component or low-level program that
acts as a Virtual Machine Manager(VMM).
 Hypervisor is a form of virtualization software used in Cloud
hosting to divide and allocate the resources on various
pieces of hardware.
 The program which provide partitioning, isolation or
abstraction is called virtualization hypervisor.
 Hypervisor is a hardware virtualization technique that allows
multiple guest operating systems (OS) to run on a single host
system at the same time. A hypervisor is sometimes also called
a virtual machine manager(VMM).
 There are two types of hypervisor:
Type 1 and Type 2
 Types of Hypervisors
6

 Type 1 hyper visors r un directly on the system hardware.

They are often referred to as a "native" or "bare metal" or
"embedded" hyper visors in vendor literature.
 It dose not require any base server operating system.It has direct
access to hardware resources

 Type 2 hypervisors run on a host operating system that provides

virtualization ser vices, suc h as I/O device and memory
management.
 Basically a software installed on an operating system, they are
often referred to as a “Hosted Architecture" hyper visors in
vendor literature.
 Type-1 Hypervisor
7
Hypervisors
 Features of Type-1 and 2 Hypervisor

Type-1 Hypervisor:
 provides better performance
 provides greater flexibility
 Ser vers that run Type 1 hypervisors are often single-purpose ser vers that offer
no other function.
 Type 1 hyper visors are production hyper visors or hyper visors that run VMs
offering ser vices to users.
 support hardware virtualization.
Type-2 Hypervisor:
 Less efficient
 Less flexible
 offer a series of different ser vices.
 rarely used in production.
 perform software virtualization.
Virtualization
 Types of Virtualization

 Hardware Virtualization
 Software Virtualization
 Memory Virtualization
 Storage Virtualization
 Data Virtualization
 Network Virtualization
 Desktop Virtualization
 Hardware Virtualization
• Hardware virtualization installs a hypervisor or virtual machine manager (VMM),
which creates an abstraction layer between the software and the underlying
hardware.
• Hardware virtualization also known as ser ver virtualization runs on the concept that an
individual independent segment of hardware or a physical ser ver, may be made up of
multiple smaller segments of hardware or ser vers, essentially consolidating multiple
physical ser vers into virtual ser vers that run on a single primary physical ser ver.
• When the virtual machine software or virtual machine manager (VMM) is directly
installed on the hardware system is known as hardware virtualization.
• The main job of hypervisor is to control and monitoring the processor, memory and
other hardware resources.
• For example, rather than buying 10 separate servers to host 10 physical applications,
a single virtualized server could potentially host those same 10 applications installed
on 10 VMs on the same system.
• Popular hypervisors include VMware's vSphere, based on ESXi, and Microsoft's
Hyper-V.
 Hardware Virtualization:Subtypes

 Full Virtualization –
• The underlying hardware is fully simulated.
• Hypervisor role is important.
• Guest software does not require any modifications.
 Para-virtualization –
• The hardware is not simulated instead the guest software run their
own isolated domains.
• Hypervisor role less important.
 Emulation Virtualization –
• The virtual machine simulates the hardware and becomes
independent of it.
• No need of Hypervisor.
• Guest software does not require any modifications.
 Hardware Virtualization:Subtypes

• Full virtualization is a common and cost-effective type of

virtualization, which is basically a method by which computer service
requests are separated from the physical hardware that facilitates
them.
• With full virtualization, operating systems and their hosted software
are run on top of virtual hardware. Full virtualization allows
administrators to run multiple operating systems simultaneously on the
same computer.
• It differs from other forms of virtualization (like paravirtualization
and hardware-assisted virtualization) in its total isolation of guest
operating systems from their hosts.
• Fully simulates the hardware to enable a guest OS to run in an isolated instance. In a fully
virtualized instance, an application would run on top of a guest OS, which would operate on
top of the hypervisor and finally the host OS and hardware. Full virtualization creates an
environment similar to an OS operating on an individual server.
 Full virtualization
• Full virtualization is fulfilled by the
use of both binary translation and
direct execution.

• In full virtualization, guest OS is

completely isolated by the virtual
machine from the virtualization layer
and hardware.

• Microsoft and Parallels systems are

examples of full virtualization.
Para-virtualization
• The hardware isn't necessarily simulated in
paravirtualization but uses an application program
interface (API) that can modify guest OSes. To modify
the guest OS, the source code for the guest OS must
be accessible to replace portions of code with
customizable instructions, such as calls to VMM APIs.
• Paravirtualization is a type of virtualization where
software instructions from the guest operating
system running inside a virtual machine can use
“hypercalls” that communicate directly with the
hypervisor. This provides an interface very similar to
software running natively on the host hardware.
• In paravirtualization, guest OS is not completely
isolated but it is partially isolated by the virtual
machine from the virtualization layer and hardware.
• VMware and Xen are some examples of
paravirtualization.
 Hardware Virtualization:
Subtypes

Full Virtualization Para Virtualization Emulation

 Software Virtualization
•Software Virtualization involves the creation and operation
of multiple virtual environments on the host machine.
•Software virtualization is just like a virtualization but able
to abstract the software installation procedure and create
virtual software installations.
• It is used to enable a complete computer system in order
to allow the guest operating system to run.
•For instance, letting LINUX OS to run as a guest that is
natively using a Microsoft Windows OS.
•In software virtualizations, an application will be installed
which will perform the further task. One software is physical
while others are virtual as it allows 2 or more operating
system using only one computer.
 Software Virtualization
Testing- It is easier to test the new operating system and software on
VMs as it does not require any additional hardware and the testing can
do within the same software.
Utilization- In software virtualization, there is higher efficiency in
resource utilization if it tunes correctly.
Efficient-It is efficient in a way such that it can run 12 virtual machines
and eliminates the use of 12 physical boxes. This is the power cost as
well as the cost of maintaining the server.
Flexible-It provides flexibility to the user so that the user can modify the
software as per their demand.
Secure-It can protect with many hantaviruses. Moreover, there are
several firewalls which prevent hacking and virus.
 Software Virtualization :Subtypes

 Operating System Virtualization –

hosting multiple OS on the native OS Example- VMware software.
 Application Virtualization –
hosting individual applications in a virtual environment separate from
the native OS Example- VMware horizon
 Ser vice Virtualization –
hosting specific ser vices related to a particular application. This is
a type of virtualization that simulates the behavior of some component in
the combination component-based application.
Example- Database virtualization: Applications depend on databases for
storing and retrieving data. Although directly accessing the production
database might be impractical during testing or development. But thanks to
service virtualization, developers and testers have a clear virtual database
mimicking actual database behavior.
 Memory Virtualization
•Memory virtualization is a key technology in cloud computing that allows multiple
users and applications to share a pool of memory, even when they are running on
different servers. This process creates a virtual memory layer that can be accessed
by applications and processes
•Memory virtualization is a technique that abstracts, manages, and optimizes
physical memory (RAM) used in computer systems. It creates a layer of abstraction
between the RAM and the software running on your computer. This layer enables
efficient memory allocation to different processes, programs, and virtual machines.
•
•Efficient resource allocation- Memory virtualization ensures that resources are used
efficiently, preventing waste and improving overall system performance.
•Flexibility and scalability- Memory virtualization allows resources to be easily adjusted
to meet changing user needs. This makes cloud computing a cost-effective solution for
businesses.
•Improved system responsiveness- Memory virtualization reduces the risk of memory-
related bottlenecks and improves overall system responsiveness.
 Memory Virtualization: Subtypes
Isolation between applications-Each process has its own virtual memory space,
which prevents processes from interfering with each other's memory.
Increased address space-Memory virtualization allows processes to use a larger
address space than what is physically available.
Application-level control – Applications access the memory pool directly.

 Operating system level control – Access to the memory pool is provided

through an operating system.
 Storage Virtualization
•Storage virtualization software has the ability to pool
and abstract physical storage resources, and present them
as a logical storage resources, such as virtual volumes,
virtual disk files, and virtual storage systems.
•Multiple physical storage devices are grouped together,
whic h then appear as a single storage device.

•This provides various advantages suc h as homogenization of

storage across storage devices of multiple capacity and speeds,
reduced downtime, l o a d balancing and better
o p t i m i z a t i o n o f performance and speed.

•Partitioning your hard drive into multiple partitions is an

example of this virtualization.
Storage Virtualization
• Combining physical storage: Multiple physical disks are combined into a
single grouping that uses a single server.
• Centralizing management: A central console manages the storage.
• Separating hardware and software: Storage management software is
separated from the underlying hardware infrastructure.
• Hiding complexity: The complexity of underlying storage systems is hidden.
• Aggregating storage: Multiple storage devices are aggregated into storage
pools.
• Intercepting I/O requests: Virtual storage software intercepts I/O requests
from physical or virtual machines and sends them to the appropriate physical
location
Storage Virtualization: Subtypes
 Storage Virtualization: Subtypes
1. Block Virtualization – Virtualisation on block level means
that storage capacity is made available to the operating
system or the applications in the form of virtual disks.

2. File Virtualization
Virtualisation on file level means that the virtualisation
entity provides virtual storage to the operating systems or
applications in the form of files and directories
 Data Virtualization
•It lets us to easily manipulate
data, as the data is
pr e se nte d as a n a b s tract
laye r com ple tel y
independent of data
str ucture and database
systems.
•Decreases data input and
formatting errors.
 Network Virtualization
22

 In network virtualization, multiple sub-networks can

be created on the same physical network, which
may or may not is authorized to communicate with
each other.
 This enables restriction of file movement across
networks and enhances security, and allows better
monitoring and identification of data usage.
 It also increases reliability as a disruption in one
network doesn’t affect other networks, and the
diagnosis is easier.
Network Virtualization :Subtypes

 Internal network:
Enables a single system to
function like a network

 External network:
Consolidation of
multiple networks into a
single one, or
segregation of a single
network into multiple
ones
 Desktop Virtualization
•Desktop virtualization allows creating and storing different
user desktop instances on a single host, living in a data center
or the cloud. It is achieved by using a hypervisor (virtual
machine monitor), which lives on top of the host server
hardware to run and allows virtual desktops to use the
computing power of the basic server hardware.
•This is perh a p s t h e m o s t c o m m o n fo r m o f
virtualization for any regular IT employee.
•The user’s desktop is stored on a remote server, allowing the
user to access his desktop from any device or location.
 Types of Virtualization: At a
25
Glance
 Benefits of Virtualization
Efficient resource use-Virtualization allows you to use hardware resources more efficiently by
creating virtual servers on a single computer system. This can save money on electricity, cooling, and
generators.
Faster disaster recovery-Virtualized environments allow you to regain access to IT infrastructure
quickly in the event of a disaster or cyberattack.
Improved data security-Virtualization protects your data and apps from malware, viruses, and
other threats. Cloud providers use encryption protocols to protect your data.
Increased efficiency and productivity-Virtualization allows you to manage all your virtual machines
(VMs) from a single machine, which saves time on maintenance.
Scalability-Virtual environments are inherently scalable, allowing you to easily deploy multiple
instances of the same VM to handle heavy load.
Green computing-Virtualization can help minimize power usage, carbon footprints, and energy
expenses.
Support for legacy applications-Virtualization allows you to create virtual environments that mimic
older operating systems and hardware setups. This allows you to maintain and operate outdated
software alongside newer applications.
Flexible data transfers-You can quickly and accurately assign data to the correct people and
restrict who has access to what data.
Development and testing-Developers can quickly spin up a VM without affecting the production
environment. They can also clone a virtual machine and run tests on it.
Characteristics of Virtualization

• Isolation
• Encapsulation
• Hardware Independence
• Resource Sharing
• Snapshot and Cloning
• Dynamic Resource Allocation
• High Availability and Fault Tolerance
• Scalability
 Cons of Virtualization
• High Initial Investment: While virtualization reduces costs in the long run, the initial
setup costs for storage and servers can be higher than a traditional setup.
• Complexity: Managing virtualized environments can be complex, especially as the
number of VMs increases.
• Security Risks: Virtualization introduces additional layers, which may pose security
risks if not properly configured and monitored.
• Learning New Infrastructure: As Organization shifted from Servers to Cloud. They
required skilled staff who can work with cloud easily. Either they hire new IT staff
with relevant skill or provide training on that skill which increase the cost of company.
• Data can be at Risk: Working on virtual instances on shared resources means that our
data is hosted on third party resource which put’s our data in vulnerable condition.
Any hacker can attack on our data or try to perform unauthorized access. Without
Security solution our data is in threaten situation.
How can AWS help with virtualization and cloud
computing?

By using AWS, you have multiple ways to build, deploy, and get to
market quickly on the latest technology. For example, you might benefit
from any of these services:

• Use Amazon Elastic Compute Cloud (Amazon EC2) to exercise granular

control over your infrastructure. Choose the processors, storage, and
networking that you want.
• Use AWS Lambda for serverless computing so that you can run code
without considering servers.
• Use Amazon Lightsail to implement virtual servers, storage, databases,
and networking for a low, predictable price.