Hypervisor

Hypervisor
• A hypervisor is a software that you can use to run
multiple virtual machines on a single physical
machine.
• Every virtual machine has its own operating
system and applications.
• The hypervisor allocates the underlying physical
computing resources such as CPU and memory to
individual virtual machines as required.
• Thus, it supports the optimal use of physical IT
infrastructure.
 Why it is important?
• Hypervisors are the underlying technology behind virtualization or
the decoupling of hardware from software.
• IT administrators can create multiple virtual machines on a single
host machine. Each virtual machine has its own operating system
and hardware resources such as a CPU, a graphics accelerator, and
storage. You can install software applications on a virtual machine,
just like you do on a physical computer.
• The fundamentals of virtual machines and other virtualization
technologies have enabled cloud computing services in enterprise
applications. They allow you to scale computing services efficiently
on limited hardware infrastructure.
• For example, different business departments can run different
workloads separately by using multiple virtual machines on a single
server.
 Benefit of Hypervisor
Organizations use virtualization software like hypervisors because the
software helps them to use resources efficiently and reduce hardware
investment. Virtualization brings several other benefits such as those
given below.
• Hardware independence
– A hypervisor abstracts the host's hardware from the operating
software environment. IT administrators can configure, deploy, and
manage software applications without being constrained to a specific
hardware setup. For example, you can run macOS on a virtual machine
instead of iMac computers.
• Efficiency
– Hypervisors make setting up a server operating system more efficient.
Manually installing the operating system and related software
components is a time-consuming process. Instead, you can configure
the hypervisor to immediately create your virtual environment.
 Benefit of Hypervisor
• Scalability
– Organizations use hypervisors to maximize resource usage
on physical computers. Instead of using separate machines
for different workloads, hypervisors create multiple virtual
computers to run several workloads on a single machine.
This translates to faster scalability and reduced hardware
expenditure for organizations.
• Portability
– IT teams can allocate memory, networking, processing,
and storage resources across multiple servers as needed.
They have the ability to shift workloads between machines
or platforms easily. When an application requires more
processing power, the hypervisor provides seamless access
to additional physical resources.
 Use cases of Hypervisor
• Desktop virtualization
– Employees use desktop virtualization software to emulate a
version of their workstation computing environment on the
server. This allows them to access their work applications and
files remotely.
• Resource optimization
– Companies use hypervisors to consolidate multiple computers
that perform different functions into a single server. For
example, if production, marketing, and customer support teams
run their workloads on individual physical servers, it can result
in idle resources. With a hypervisor, you can host the virtual
machines for the respective business units on a single server,
even if they require different operating systems and software
components.
• Failure recovery
– The hypervisor captures snapshots of the virtual machine’s previous
state in a virtual machine image—a file that contains the installation
instructions, configurations, and other details of the virtual machine.
– System administrators can use the image file to restore the virtual
machine in case of failure. There is also capability to create backup
copies or move the virtual machine to a different host.
• Legacy system continuity
– Some organizations have invested significantly in software that has
outlasted the underlying server.
– Hypervisors provide an option to continue running the software by
virtualizing the hardware environment required. This allows
organizations to support their cloud transformation efforts with
minimum disruption to existing business workflows.
 Types of Hypervisor
• Type 1 hypervisor
– The type 1 hypervisor sits on top of the metal
server and has direct access to the hardware
resources.
– Because of this, the type 1 hypervisor is also
known as a bare-metal hypervisor.
– The host machine does not have an operating
system installed in a bare-metal hypervisor setup.
Instead, the hypervisor software acts as a
lightweight operating system.
Type 1 hypervisor
 Type 1 hypervisor
• Pros and cons
– Due to its architecture, the type 1 hypervisor is
very efficient.
– It can directly manage and allocate resources for
multiple virtual machines without going through
the host operating system.
– These types of hypervisors are also more secure,
as the absence of a host operating system reduces
the risks of instability.
 Type 2 hypervisor
• Type 2 hypervisor
– The type 2 hypervisor is a hypervisor program
installed on a host operating system.
– It is also known as a hosted or embedded hypervisor.
– Like other software applications, hosted hypervisors
do not have complete control of the computer
resources. Instead, the system administrator allocates
the resources for the hosted hypervisor, which it
distributes to the virtual machines.
Type 2 hypervisor
 Type 2 hypervisor
• Pros and cons
– The presence of the host operating system
introduces latency to the virtualized environment.
– When the virtual machine requests computing
resources, the hypervisor cannot directly access
the underlying hardware but relays the request to
the host operating system.
– Also, the hypervisor and its hosted virtual
machines are dependent on the stability of the
host operating system.
 Type 1 hypervisors Vs type 2
hypervisors
• Despite their differences, both types of
hypervisors are helpful in different applications.
– For example, enterprise cloud data centers use type 1
or bare-metal hypervisors because of their efficiency,
scalability, and flexibility when allocating resources to
virtual machines. Also, a type 1 hypervisor is generally
more secure and stable because it does not run on top
of another operating system.
– Conversely, administrators use type 2 hypervisors
because they are more user-friendly. Type 2
hypervisors are easier to install, configure, and use
than bare-metal hypervisors. It is similar to installing
and using other desktop applications.