Virtualization

A Seminar Report On “VIRTUALIZATION” Submitted to the Rajasthan Technical University, Kota In Partial fulfillment of the requirement for the degree of MASTER OF COMPUTER APPICATIONS

Submitted By: Submitted To.

Ms. Prachi Rawal Mr. Hemant Sahu

MCA 5th Sem.(3rd Year) Assoc.Prof.&Head

Of MCA Department

by:Mr. Abhishek Khare

Fundamental

The journey toward the cloud begins with virtualization.

Virtualization has emerged as the key disruptive technology that has catalyzed and enabled data centres to deliver cloud services.

Compute, networks, and storage form the three infrastructure pillars of today’s data centre.


Contd.

The idea of virtualization is not new; it has been around since the days of the mainframe.

But more recently, the term virtualization has gained a broader, more inclusive connotation beyond server virtualization.


Virtualization Basics Virtualization can be defined as the abstraction of

physical resources into logical units, such that a single physical resource can appear as many logical units and multiple physical resources can appear as a single logical unit.

The primary motivation behind virtualization is to hide the physical characteristics and irrelevant details of these resources from their end users.

Thus, each user gets the illusion of being the lone user of that physical resource (one-to-many virtualization). Or multiple physical resources appear as a single virtual resource to the user (many-to-one virtualization).


One to Many

Consider the familiar example of virtualizing an x86 server, where software, called virtual machine monitor (VMM) or hypervisor , allows multiple virtual machines (VM) to run on the same physical server, as illustrated in Figure


Contd.


Contd. Each VM emulates a physical computer by

creating a separate operating system environment.

The ability to run multiple VMs means that we can now simultaneously host multiple operating systems on the same underlying physical machine. Each operating system gets the illusion that it is the only one running on that host server.

One physical machine has effectively been divided into many logical ones.


VLAN

Virtual LANs (VLAN) are another example of one-to-many virtualization, where a single physical network is partitioned into many logical ones.

Instead of setting up separate physical networks for each user group, a single physical network infrastructure can suffice, with each user group assigned to a separate logical network (VLAN).


Many to One

The classic example for many-to-one virtualization is that of a load balancer, which front ends a group of web servers. As shown is Figure


Contd.


Contd.

The load balancer hides the details about the multiple physical web servers and simply exposes a single virtual IP (VIP).

The web clients that connect to the VIP to obtain the web service have the illusion that there is a single web server.

Many physical web servers have been abstracted into one logical web server.


Virtualization: A Brief History The concept of virtualization has

been around since the 1960s, when IBM implemented it to logically partition mainframe computers into separate VMs.

This partitioning enabled mainframes to run multiple applications and processes at the same time, which improved their utilization.

Such multitasking allowed better leveraging of those expensive investments.


Contd. Over the next two to three decades, the need for

virtualization declined as inexpensive PCs and servers became available.

In addition, client/server applications became prevalent, and the trend shifted toward distributed computing. Furthermore, the universal adoption of Windows and Linux led to the emergence of x86 servers as the dominant compute platforms.

Unlike mainframes, however, these servers have not been designed for virtualization. To enable the virtualization of x86 servers, specialized software called hypervisor was developed by companies such as VMware, Citrix, Microsoft, and others.


Contd. The term virtualization has evolved beyond server

virtualization into a significantly broader context. Today, it represents any type of process

obfuscation where a process is removed from its physical operating environment.

Therefore, virtualization can be applied to other areas of IT, such as storage, network, applications, services, desktops, and many more.

This chapter focuses on server virtualization, network virtualization, and storage virtualization, which together form the foundation of today’s virtualized data center.


Server Virtualization Server or compute virtualization is the most

popular and visible form of virtualization today. We briefly touched on this form of virtualization

as an example of one-to-many virtualization and saw how low-level software (hypervisor or VMM) allows multiple operating systems to run concurrently on a single host computer.

As Figure 1-1 illustrated, each operating system, along with its applications, runs in complete isolation as a VM on top of the hypervisor, under the illusion that it is the sole operating system running on that physical machine.


Contd.

To successfully virtualize the system and enable multiple VMs to run concurrently on the same host, hypervisors dynamically partition and share the available physical resources, such as CPU, memory, and I/O devices. The functionality of the hypervisor varies greatly based on the architecture and implementation.


Contd.


Components of Server Virtualization CPU, memory, and I/O are typically

considered the three vital resources of a server.

Correspondingly, the three key components of server virtualization are CPU virtualization, memory virtualization, and I/O virtualization . The sections that follow take a look at all three components, starting with the virtualization of the x86 CPU.


Memory Virtualization Beyond CPU virtualization, the other critical

part of server virtualization is memory virtualization. This involves sharing the host physical memory (machine memory) and dynamically allocating it to VMs, as illustrated in Figure 1-4 .

VM memory virtualization is similar to the virtual memory support provided by modern OS.


Contd. Applications see a contiguous address

space that is not necessarily tied to the underlying physical memory in the system.

The operating system keeps mappings of virtual page numbers to physical page numbers stored in page tables.

All modern x86 CPUs include a memory management unit (MMU) and a translation look-aside buffer (TLB) to optimize virtual memory performance.


Contd.


I/O Virtualization Having covered VMs (CPUs) and then virtual

memory, this discussion now turns to the final component of the server virtualization story: I/O virtualization (IOV).

As the name suggests, IOV involves virtualizing the I/O path from the server to the peripheral device, enabling multiple VMs to share an I/O device.

As shown earlier in the case of CPU and memory virtualization, even in IOV we have a software approach and a hardware approach.


Virtual Storage Area Network (VSAN)

A virtual storage area network (VSAN) is a logical partition in a storage area network (SAN). VSANs allow traffic to be isolated within specific portions of a storage area network.


Contd. The use of multiple VSANs can make a system

easier to configure and scale out. Subscribers can be added or relocated without the need for changing the physical layout.

If a problem occurs in one VSAN, that problem can be handled with a minimum of disruption to the rest of the network.

Because the independence of VSANs minimizes the total system's vulnerability, security is improved. VSANs also offer the possibility of data redundancy, minimizing the risk of catastrophic data loss.

http://searchdatacenter.techtarget.com/definition/scalability


Contd.

The term is most often associated with Cisco Systems and is often mentioned in conjunction with the zoning. Zoning splits a SAN into multiple, isolated subnetworks.

The concept behind a VSAN is often compared to that of a virtual local area network (VLAN).

VLANs segregate broadcasts from other networks

http://searchstorage.techtarget.com/definition/zoning

http://searchnetworking.techtarget.com/definition/virtual-LAN


VLAN

In computer networking, a single layer-2 network may be partitioned to create multiple distinct broadcast domains, which are mutually isolated so that packets can only pass between them via one or more routers; such a domain is referred to as a virtual local area network, virtual LAN or VLAN.

http://en.wikipedia.org/wiki/Computer_network

http://en.wikipedia.org/wiki/Data_link_layer

http://en.wikipedia.org/wiki/Network_segmentation

http://en.wikipedia.org/wiki/Broadcast_domain

http://en.wikipedia.org/wiki/Router_(computing)


Thanks!!!!!!!!

Virtualization

Technology