VIRTUALISATION

--PRIYA SRIVASTAVA

(090105801)

E.I III YR.

INTRO

Virtualization is a framework or methodology of dividing the resources of a computer into multiple execution environments,

Done by applying one or more concepts or technologies such as:

Hardware & software partitioning, Time-sharing, Partial or complete machine simulation, Emulation, Quality of service, And many others. “Virtualization is an abstraction layer that decouples

the physical hardware from the operating system to deliver greater IT resource utilization & flexibility”.

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.

BRIEF HISTORY

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).

How Does Virtualization Work?

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. VMware virtualization 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 architecturewithout virtualization

The binary translationapproach to x86 virtualization

The Paravirtualization approach to x86Virtualization

The hardware assist approach to x86virtualization

Memory Virtualization

Device and I/O virtualization

DIFFERENT TYPES OF VIRTUAL MACHINES

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.

HARDWARE LEVEL VIRTUALISATION

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

Operating System Level Virtualization

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. What have we seen in lab that acts like this?

Operating System Level Virtualization

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. What have we seen in lab that acts like this?

Real Machine

OS

VMM

Virtual Machine

Application

Applications

High-level Language Virtual Machines

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

Seven reasons to consider virtualization

 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

Countless Other Virtualization Technologies…

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

The Future

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)

ARE YOU READY FOR VIRTUALISATION

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.