Virtualization
COMP 2130
Content
Virtualization
Hypervisor
Types
Types of Virtualization
Virtualisation
Virtualization refers to the creation of a virtual version of something, such as a computer
hardware platform, an operating system, a storage device, or a network resource.
It allows multiple virtual instances to run on a single physical machine, effectively maximizing
the utilization of hardware resources.
Virtualization involves creating virtual machines (VMs) that are isolated from the physical
hardware and can run their own operating systems and applications.
Virtualization enables multiple VMs to run on a single physical server, which can reduce
hardware costs and increase efficiency.
Hypervisor
A hypervisor is generally considered mandatory for virtualization.
A hypervisor is a type of software or hardware used to create virtual machines and then run
those virtual machines day to day.
It acts as a layer that enables multiple virtual machines to run on a single physical
machine/server.
It provides a way for the virtual machines to share the physical resources of the host machine,
such as CPU, memory, and storage.
Role of hypervisors
A hypervisor is essential for virtualization because
◦ it creates and manages the virtual machines,
◦ allocates the physical resources to them, and
◦ provides a layer of abstraction that allows the virtual machines to operate independently of
each other.
Without a hypervisor, it would be difficult to manage multiple virtual machines
running on a single physical machine, and the virtual machines would not be
able to share resources efficiently. Therefore, a hypervisor is considered a
fundamental component of virtualization.
However, we can achieve virtualization using other ways as well.
Hypervisor working
A hypervisor sits between the physical hardware of a host machine and the virtual machines
running on that machine.
Depending on the type, it might sit right on top of the hardware or it on the O/S.
Either way, hypervisors translate VM requests, which are by definition virtual, for the physical
hardware on which the operations must still run.
A parent and child relationship exists between the host machine (parent) and the virtual
machines running on it (children).
Parent
Children
Host Machine (Parent)
Virtual Machines (Children)
Physical machine on which hypervisor is installed
The virtual machines running on the host machine are
called children or guests.
It provides the resources that the hypervisor uses to
create and manage the virtual machines.
They are isolated from each other and from the host
machine
Each VM have their own virtual hardware and operating
system.
Responsible for managing the hardware resources, such
as
• CPU,
• memory,
• storage, and
• network,
• and it provides those resources to the hypervisor as
needed.
The hypervisor manages the resources allocated to each
virtual machine and provides each one with its own
virtual hardware environment.
The parent-child relationship between the host machine and virtual machines is important
because it determines the level of isolation and security between the virtual machines.
The hypervisor ensures that each virtual machine is isolated from the others and from the host
machine, preventing them from interfering with each other or accessing each other's data.
Hypervisor types
Type -1
Type -2
Type 1 hypervisor replaces the host’s operating system and lies right on top of the hardware.
For this reason, type 1 hypervisors are also called bare metal /native hypervisors or embedded
hypervisors.
Examples:
◦ VMware hypervisors like vSphere, ESXi and ESX
◦ Microsoft Hyper-V
◦ Oracle VM Server
Type 1 hypervisors are typically used in enterprise data centres and cloud environments, where
performance and security are critical.
These hypervisors run on top of an existing operating system and provide virtualization services
through that operating system.
Type 2 hypervisors are typically used on personal computers and workstations, where they can be
used to run multiple operating systems and applications simultaneously.
Example:
◦
◦
◦
◦
VMware Workstation
VMware Fusion
Oracle VirtualBox
Oracle Solaris Zones
We will use Type – 2 hypervisor to create a virtual machine (Linux OS) on personal systems
Types of virtualisation
Data Virtualization
Desktop Virtualization
Server Virtualization
Operating System Virtualization
Network functions Virtualization
Data Virtualization
Data virtualization is a technology that allows an
application or user to retrieve and manipulate data
from different sources, such as databases, cloud
storage, or web services, as if it were coming from a
single, unified source.
The underlying physical location of
the data is abstracted away, and
the data is presented in a
virtualized form to the application
or user.
Desktop Virtualization
Desktop virtualization allows a central administrator
or automated administration tool to deploy virtual
desktop environments to multiple physical machines
simultaneously.
Instead of installing and configuring each individual
physical machine, the administrator can create a
single virtual desktop environment and deploy it to
hundreds of physical machines at once.
Server Virtualization
Server virtualization is a technology that allows
multiple virtual servers to be created and run
on a single physical server.
Instead of having a dedicated physical server
for each workload or application, a single
physical server can be shared among multiple
virtual servers, each of which has its own
operating system and applications.
Operating System Virtualization
Operating system virtualization happens
at the kernel—the central task managers
of operating systems. It’s a useful way to
run Linux and Windows environments
side-by-side.
Network functions virtualization (NFV)
It separates a network's key functions (like
directory services, file sharing, and IP
configuration) so they can be distributed among
environments.
Once software functions are independent of the
physical machines they once lived on, specific
functions can be packaged together into a new
network and assigned to an environment.