VIRTUALIZATION

Virtualization is a framework or methodology of

dividing the resources of a computer into multiple

execution environments.

It can also be explicate as an abstraction layer that

decouples the physical hardware from the operating

system to deliver greater IT resource utilization &

flexibility”.

It is done by applying one or more concepts or

technologies such as:

Time-sharing,

Partial or complete machine simulation,

Hardware & software partitioning,

Emulation,

Quality of service,

And many others. . .

Virtualization technology enables multiple operating

systems and application ‘images’ to share a single

physical server.

A virtual server, or what is commonly known as a

‘virtual machine’, simulates the operations of your

servers.

This enables an application to run on a machine as it

would on a physical server.

Its NOT A NEW CONCEPT

1960’s at IBM:

M44/44X Project - the goal of which was being to evaluate the then emerging time sharing system concepts.

The architecture was based on virtual machines:

The main machine was an IBM 7044(M44) and each virtual machine was an experimental image of the main machine(44X).

IBM & MIT headed research through the years & eventually developed the idea of a virtual Machine Monitor(VMM).

The VMware virtualization platform is built on a BUSINESS-

READY ARCHITECTURE.

Use software such as VMware vSphere to transform or

“virtualized” the hardware resources of an x86-based computer—

including the CPU, RAM, hard disk and network controller—to

create a fully functional VIRTUAL MACHINE that can run its own

operating system and applications just like a “real” computer.

Each virtual machine contains a complete system, eliminating

potential conflicts. It works by inserting a thin layer of software

directly on the computer hardware or on a host operating system.

This contains a virtual machine monitor or “hypervisor” that

allocates hardware resources dynamically and transparently.

Multiple operating systems run concurrently on a single

physical computer and share hardware resources with each

other.

By encapsulating an entire machine, including CPU, memory,

operating system, and network devices, a virtual machine is

completely compatible with all standard x86 operating

systems, applications, and device drivers.

We can safely run several operating systems and applications

at the same time on a single computer, with each having

access to the resources it needs when it needs them.

x86 privilege

level architecture

without

virtualization

The binary

translation

approach to x86

virtualization

The

Paravirtualization

approach to x86

Virtualization

The hardware assist

approach to x86

virtualization

Memory Virtualization

Device and I/O virtualization

Modern computer systems are composed of various hardware

& software layers.

Virtualization inserts a software layer(VMM) at different

points in this architecture, comes in three variants:

Hardware-level virtualization,

Operating system-level,

High-level language virtual

machines.

Virtualization layer sits right on top of the real hardware.

Since the VM presents a version the real machine, all software

written for that hardware(x86) will run on that virtual

machine.

Original design from IBM in the 1960’s

Virtualization layer sit between the operating system and the

application programs that run on the operating system

Virtual Machine runs applications, or sets of applications

written for the operating system but in a controlled

environment

use host OS API

FreeBSD jails act like this.

The virtualization layer sits as an application program on top of the operating system

Can run any programs written for that virtual machine abstraction regardless of the operating system hosting that virtual machine Real Machine

OS

JVM

Java Byte Code

Applications

It enables us to get the most out of our server hardware.

It will allow us to set up redundant servers for better fault

tolerance.

Management is simplified.

We can partition applications on separate OSes for greater

reliability.

Provisioning new servers for prototyping, testing and

migration is simplified.

We can save energy.

Virtual Desktop Infrastructure can save us a fortune on PCs

SimOS Microsoft Virtual Server Mac-on-Linux Linux-VServer OpenVZ Microsoft Virtual PC

Hardware companies have taken notice of virtualizations growing popularity and advantages

Intel (called Virtualization Technology or VT-X Vander pool) and AMD (Pacifica) are releasing processors that have built in software virtualization support that try to eliminate emulation costs

This support will allow Xen to support unmodified unprivileged OS’s (hello Windows support)

Many organizations across Australia are starting to take

advantage of server virtualization to reduce power, cooling

and equipment costs, reduce server administration and

downtime, and gain a higher level of server redundancy.