2. Learning Objectives
↘ Understand the basics of virtualization
↘ Understand how the different resources such as
processors, memory, storage, and network can be
virtualized
↘ Understand the pros and cons of different approaches to
virtualization
↘ Understand the basics of hypervisor and its security
issues
↘ Understand how cloud computing is different from
virtualization
↘ Understand how cloud computing leverages the
virtualization for its different service models
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3. Virtualization
↘Virtualization is the idea of partitioning or
dividing the resources of a single server into
multiple segregated VMs.
↘Virtualization is the idea of dividing a single
hard ware or software into multiple system
↘Virtualization technology has been proposed
and developed over a relatively long period.
↘The earliest use of VMs was by IBM in 1960,
intended to leverage investments in expensive
mainframe computers 3
4. Virtualization
↘Virtualization refers to the act of creating a
virtual (rather than actual) version of
something, including (but not limited to) a
virtual computer hardware platform,
operating system (OS), storage device, or
computer network resources.
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7. Virtualization Opportunities
↘Virtualization is the process of abstracting the
physical resources to the pool of virtual resources
that can be given to any virtual machines (VMs).
The different resources can be virtualized:
1. memory
2. processors
3. storage
4. network
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8. Processor Virtualization
Processor virtualization allows the VMs to share
the virtual processors that are abstracted from
the physical processors available at the
underlying infrastructure.
The virtualization layer abstracts the physical
processor to the pool of virtual processors that is
shared by the VMs. The virtualization layer will be
normally any hypervisors.
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10. Memory Virtualization
The process of providing a virtual main memory to the
VMs is known as memory virtualization or main memory
virtualization.
Main memory virtualization can also be achieved by using
the hypervisor software. Normally, in the virtualized data
centers, the unused main memory of the different servers
will consolidate as a virtual main memory pool and can be
given to the VMs.
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12. Storage Virtualization
Storage virtualization is a form of resource
virtualization where multiple physical storage disks
are abstracted as a pool of virtual storage disks to
the VMs. Normally, the virtualized storage will be
called a logical storage.
The other advanced storage virtualization
techniques are storage area networks (SAN) and
network-attached storage (NAS).
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14. Network Virtualization
Network virtualization is a type of resource virtualization
in which the physical network can be abstracted to create
a virtual network.
Normally, the physical network components like router,
switch, and Network Interface Card (NIC) will be
controlled by the virtualization software to provide virtual
network components.
The virtual network is a single software-based entity that
contains the network hardware and software resources.
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16. Data Virtualization
Data virtualization is the ability to retrieve the data
without knowing its type and the physical location where
it is stored. It aggregates the heterogeneous data from
the different sources to a single logical/virtual volume of
data.
This logical data can be accessed from any applications
such as web services, E-commerce applications, web
portals, Software as a Service (SaaS) applications, and
mobile application.
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18. Application Virtualization
Application virtualization is the enabling technology for
SaaS of cloud computing.
The application virtualization offers the ability to the user to
use the application without the need to install any software
or tools in the machine. Normally, the applications will be
developed and hosted in the central server.
The hosted application will be again virtualized, and the
users will be given the separated/isolated virtual copy to
access.
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20. Briefly About Virtualization
Hypervisor/Virtual Machine
Monitor
Host Operating System
Guest Operating System
Every Virtual Machine is given a
set of virtual hardware.
Involves many software and
hardware architectural
modifications. (Memory
Management, CPU
Management)
20 of
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21. When would we use virtualization
Running different operating system in one computer
To make best use of computer hardware
Maintaining capability with older system
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22. Approaches to Virtualization
There are three different approaches to virtualization.
Before discussing them, it is important to know about
protection rings in OSs.
Protection rings are used to isolate the OS from
untrusted user applications.
The OS can be protected with different privilege levels. In
protection ring architecture, the rings are arranged in
hierarchical order from ring 0 to ring 3
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24. Cont.
There are three types of approaches followed for
virtualization:
1. Full virtualization
2. Para virtualization
3. Hardware-assisted virtualization
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25. 1.Full Virtualization
Full virtualization is a technique in which a complete
installation of one machine is run on another.
• –The result is a system in which all software running
on the server is within a virtual machine
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26. Type of virtualization cont..
In a fully virtualized deployment, the software running on the
server is displayed on the clients.
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27. Type of virtualization cont..
Virtualization is relevant to cloud computing because
it is one of the ways in which you will access services
on the cloud.
That is, the remote datacenter may be delivering
your services in a fully virtualized format.
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28. Type of virtualization cont..
Full virtualization has been successful for several
purposes:
Sharing a computer system among multiple users
Isolating users from each other and from the control
program
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29. Partial virtualization
Partial virtualization allows multiple operating
systems to run on a single hardware device at the same
time by more efficiently using system resources, like
processors and memory
Partial virtualization typically runs better than the full
virtualization model.
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31. Hardware-Assisted Virtualization
In the two previous approaches, there is an additional
overhead of binary translation or modification of guest OS
to achieve virtualization.
But in this approach, hardware vendors itself, like Intel and
AMD, offer the support for virtualization, which eliminates
much overhead involved in the binary translation and guest
OS modification.
Popular hardware vendors like Intel and AMD has given
the hardware extension to their x86-based processor to
support virtualization. For example, the Intel releases its
Intel Virtualization Technology (VT-x) and AMD releases its
AMD-v to simplify the virtualization techniques.
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32. Cont.
In hardware-assisted virtualization, the VMM has the
highest privilege (root privilege) level even though it is
working below ring 0.
The OS resides at ring 0 and the user application at ring 3.
Unlike the other virtualization approaches, the guest OS
and the user applications are having the same privilege
level (non root privilege level).
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35. Benefits
Virtualization can help companies maximize the value of
IT investments, decreasing the server hardware, energy
consumption, and cost and complexity of managing IT
systems while increasing the flexibility of the overall
environment.
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36. Benefits
But there are also reduced costs across your organization.
If you reduce the number of physical servers you use, then
you save money on hardware, cooling, and electricity.
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37. hypervisor
A hypervisor, also called a virtual machine manager
(VMM), is a program that allows multiple operating
systems to share a single hardware host.
Each operating system appears to have the host's
processor, memory, and other resources all to itself.
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38. What is a hypervisor?
The virtualization tools or hypervisor is the low level
program that allows multiple operating systems to run
concurrently on a single host computer.
hypervisor has two type:
1.native or bare-metal hypervisors
2.hosted hypervisors
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39. Native or bare-metal hypervisors
These hypervisors run directly on the host's hardware to
control the hardware and to manage guest operating
systems.
For this reason, they are sometimes called bare metal
hypervisors. A guest operating system runs as a process
on the host.
Example: Xen Server, VMware ESX/ESXi and Microsoft
Hyper-V 2008/2012.
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41. hosted hypervisors
These hypervisors run on a conventional operating
system just as other computer programs do.
Type-2 hypervisors abstract guest operating systems
from the host operating system.
For example: VMware Workstation, VMware Player and
Virtual Box
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44. ESX & ESXi
ESX (Elastic Sky X) is the VMware’s enterprise server
virtualization platform.
In ESX, VMkernel is the virtualization kernel which is
managed by a console operating system which is also called
as Service console.
Which is linux based and its main purpose is to provide a
Management interface for the host and lot of management
agents and other third party software agents are installed
on the service console to provide the functionalists like
hardware management and monitoring of ESX hypervisor. 44
46. ESXi Compare to ESX
ESXi (Elastic sky X Integrated) is also the VMware’s enterprise
server virtualization platform.
In ESXi, Service console is removed. All the VMware related
agents and third party agents such as management and
monitoring agents can also run directly on the VMkernel.
ESXi uses Direct Console User Interface (DCUI) instead of a
service console to perform management of ESXi server. ESXi
installation will happen very quickly as compared to ESX
installation.
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49. VMotion
VMotion allows you to
quickly move an entire
running virtual machine
from one host to
another.
The entire state of a
virtual machine is
encapsulated and the
VMFS file system allows
both the source and the
target ESX host to access
the virtual machine files
concurrently.
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50. Storage VMotion
Storage VMotion is a
new feature introduced in
ESX 3.5, it allows you to
migrate a running virtual
machine and its disk files
from one datastore to
another on the same ESX
host
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51. HighAvailability (HA)
Continuously monitors all hosts
in a cluster and restarts virtual
machines affected by a host
failure on other hosts
Can also monitor guest OS's for a
failure via a heartbeat and restart
them on the same host in case of
a failure
Continuously monitors and
chooses the optimal physical
servers within a resource pool on
which to restart virtual machines 51
53. Summary
• Virtualization is a widely used technology in the IT industry to increase resource
utilization and ROI. It allows the same physical infrastructure to be shared between
multiple OSs and applications. The other benefits of virtualization include dynamic
data center, green IT support, ease of administration, and improved disaster
recovery. There are three types of approaches used to achieve virtualization, namely
full virtualization, paravirtualization, and hardware-assisted virtualization. Full
virtualization completely abstracts the guest OS from the underlying infrastructure.
Paravirtualization provides partial abstraction of the guest OS from the underlying
infrastructure with slight modification of the guest OS. In hardware-assisted
virtualization, the hardware vendor itself offers the support for virtualization.
Hypervisors are the key drivers in enabling virtualization in large-scale cloud data
centers. There are two types of hypervisors available, namely type 1 or bare metal
hypervisor and type 2 or hosted hypervisors.
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