Lecture 2 : Virtualization

Introduction to virtualization

• Virtualization will create a virtual version of a device or resource , such as a server , storage device, network, or even an operating system where the framework divides the resource into one or more execution environments
• virtualization is part of an overall trend in enterprise IT that includes autonomic computing , which is a scenario in which the IT environmnet will be able to manage itself based on perceived activity and utility computing , in which the processor's poer is seen as a utility that clients can pay for as needed

4 trends

• Mainframe computers have offered the ability to host multiple operating systems for more than 40 years , hence virtualization is not new
• however , four trends have converged in recent years that have allowed virtualization to migrate from the exclusive domain of mainframe computers to a front and center position in todays's computing environmetn
• 4 trends
• 1) hardware is under utilized
• 2) Data centers are running out of space
• 3) energy costs are skyrocketing
• 4) system administration cost are increasing

Hardware is under utilized

• Moore's law demonstrates increasing returns the amount of improvement in processeor speed grows over time because there is an exponential increase in capacity for every generation of processor improvement
• many data centers today have machines running at only 10-15% of the total processing capacity. in other 85-90 of the machine's power is unused
• in a way moore's law is no longer relevant to most companies bec trrhey are not able to take advantage of the increased power available to them
• by applying virtualization , organizations can improve their hardware utilizaTION FROM 10-15 TO 70-80

Data cenetrs are running out of space

• 20 years ago the vast majority of business processes were paper based . computerized systems were confined to so called backroom automatin : payroll , accounting , and the like
• partly due to moore's law, this has all changed with business process after business process being captured in software and automated . the rise of internet has exponentially increased this transformation as well

energy costs are skyrocketing

• overall increasing cost of energy , worldwide:
• increasing computization means that companies are using more power than ever,
• escalating energy costs now make ealectricity none of the top five costs in many company's operation budgets

System administration costs are increasing

• Computer systems do not operate on their own . every server requires proper care and feeding by system administrators who as part of the operations group , ensure that the server runs properly
• system administration is labor intensive and system administartors do not come cheap
• unlike system programmers who may be offsite sytem administrators are almost always onsite due to their need to access the physical hardware
• the steady increase in the number of servers world wide has meant a very good job market for system administrators

non and virtualized system

• nonvirtualized system
• a single os controlss all hardware platfrom resources
• viirtualizized
• run multiple virtual containers on a single physical platform

computing Infrastructure

• 1 machine - 1 os -several applications
• applications can afeect each other
• big disadvantge
• machine utilization is very low most of the times it is below than 25%

Computing infrastructure -virtualization

• it matches the benefits of high hardware utilization with running several operationg systems (aPPLICATWIONS) IN A seperated virtualized environmnets
• each application runs in its own qos
• each os does not know it is sharing the underlying hardware with others

Forms of virtualization

• the typical goal of virtualization is to centralize administrative tasks while improving scalability and work loads across a system or network
• virtualization in a computing environment can be present in many different forms
• a) hardware (server) virtaulalization
• b)server clustering
• 30storage virtualization
• d) software virtualization
• e)network virtualization

Hardware virtualization

• is the execution of software in an environment seperated from the underlying hardware resources
• 1) hardware-assisted : where some suppoert for virtualization is built into the underlying ( a virtual machine has its own hardware and allows a guest os to be run in isolation )
• 2)full virtualization : provides a sufficiently complete simulation of the inderlying hardware to allow software , typically a guest os , to run unmodified ( the virtual machine asimualtes enough hardware to allow an unmodified "guest" os (on e designed for the same cpu
• to run in isolation
• 3)partial virtualization : some abut not all of the target environment is simulated . this may require that some guests be modifies on order to run in this environmnet (the virtual machine simulates multiple instances of much (but not all
• ) of an underlying hardware environmnet , particularly address spaces
• 4)paravirtualization : a virtualization environmnt in which the guest OS requires modification to run in exchange for higher efficiency (the virtual machine does not necessarily simulate hardware , but instead (or in addition
• ) offers a special API that can only be used by modifying the guest "os".

Server clustering

• A method that aloows multiple servers to be treated as a single server
• clustering is a form of virtulaization that makes several locally attached physical systems appear th the application and end usersa single processing resource
• this difer significantly form server virtualization technologies , which normally achieves the opposite effect
• usage : high volume application , or as a web farm which is a location of web servers that can all handle load based aplication

Storage virtualization

• storage virtualization is the pooling of physical storage from multiple network storage devices into what appeas to be a single storage devices that is managed from a central console
• Storage as a service is a business model in which a company leases or rents its storage infrastructure to another company or individuals to store data . small companies and individuals often find this to be a convenient methodolgy for managing backups and providing cost savings in personnel , hardware and physical space

Software virtualization

• OR OS virtualization . this allow for the hosting of multiple virtualized environmnets within a single OS instance
• application virtualization allows the hosting of individuaal applications in an environmnet seperated from the underlying OS
• VM is a software possibly a hardware assisted ipmlementation of a computer system that execautes applications like an actual, computer

Desktop virtualization

• desktop virtualization [on-premise]
• desktop virtualization help to reduce desktop IT costs, improve security , increase control and expand connectivity
• in desktop virtualization, desktops are hosted in own data cenetrs and can be accessed from any device anywhere . this allows support new business models and improve both IT operations and user satisfaction

Desktop virtualization (DaaS cloud-based)

• provides the same benefits as on-premise desktop virtualization , including reduced desktop IT costs, improved security, increased control ,a nd expanded connectivity
• additionally, services are provided from an offsite cloud-based data center
• Daas is an economical , pay-per-user approach that provides desktops and reduces the day-to -day IT responsibilities for end-user responsibiliteis foe end-user computing

Network virtualization

• Network Virtualization is a method of giving groups acess to the same physicl network capabilities while keeping them logically seperate tpo a degree that they have no visisbility into other group
• the idea is to simplify the complexity of an entire network by partionining it into manageable parts
• network virtualization achieves thsis by combining the available resouces in a network and by solitting up the available bandwidth into channels , each of which is independent from the other , and each of which can be assigned to a particular server or device

the benefits of virtualization

• A) server consolidation
• one of the primary benefits of virtualization software is that it allows you to increase the scale of you server infrastructure without purchasing addditional pieces of hardware
• B) Energy consolidation;
• in addition to savings in hardware costs , virtualization software may also save you money on your energy bill . the energy costs for running a server for a year will soon exceed the price acquiring it
• c) Ease of management
• managing virtual machines is a lot easier than managing "real" machines , since hardware upgrades for example can be done with a click of several butth=ins , rather than having to power down the machine , install the hardware , verify the change, then power up agian . moreover , managing virtual machines can often be done via a console server . thereby redducing the time needed to deplo them
• d)Reducing backup and recovery time
• since virtual machines are essentially files , backing up and restoring them is a lot less time-consuming
• while the files can be huge a directory of many 2 gb IS STILL EASIER TO RESTORE THAN A REAL machine of same specifications
• moreover, hardware failure -such as a failed hard drive - will not affect virtual machines in the same way they would a physical machine

Benefits of virtualization

• testing software configuarations another way you can use virtualization software is for testing software configuration before deploying them on a live system . if you need to verify whether a program is compatible with your existing setup , for example , you may try testing it on a vm first. this can immensely be useful for org that have a legacy system or app and must test out systems before deploying them. VM can also interact together in virtual networks , allowing you to test server-client applications virtually

Slide 20

• Maintaing a legacy application :
• if you do have old applications that have compatibility issues with newer software or that must run an a certain version of an operating system , you can dedicate a virtual machine just for those tasks . you can dedicate a vzirtual machine just for those tasks . that way your IT architecture and planning wont be contrained because of few applications
• maintaing a cross-platform office
• it is not uncommen for offices that run mostly MAc to need to run one or two windows-only program ; in this case virtual software can be affordable , easy way to do this , however reverse is not applicaBLE MANY VM FOR PCS ALLOW YOU 4TO RUN liNUX BUT NOT mAC OS

Drawbacks of virtualization

• limited scalabilty, common hardware , drain on performnaece
• Performance issue :
• virtualization software adds a certain amount of overhead to the computer system on which it is running
• Determining the overall impact that virtualization software imposes is a difficult task , but generally speaking , virtualization software has a minimal impact is imposed on the disk on networking performance of the system
• common hardware:
• Rapid provisioning and system flexibility are benefits of a common hardware arrangement . however , if the OS and applications that you want to virtualize are not capable of running on the system hardware or require other hardwre , you're out of luck with virtualization

Use of virtualization

• virtualization does not lend itself to all sitiuations . Asn an IT professional you will need to know how to recognize sitiuations in which virtualization can be beneficial to the organzization
• Virtualization can be rapidly applied are:

Application development and testing

• Virtualization allows software development to run multiple VMs rather than multiple physical machines
• when developing and testing an application , the developer might need a metwork of machines ; database server , a transaction setrver , and a client . virtualization could be used to run this network on one physical machine
• by rapid provisioning , the developer can quickly and economically create the necessart network infrastructure
• the developer caan repeatedly test the software inside of the VMs with the ability to quickly reqturn to a clean , known state after each test

Use of virtualization

• training
• ; virtual machines are great tools for implementing training and learning
• training employees about new os and computer applications involoves extensive amounts of time and hardware
• in many training environment , the trainees will be changing the system configuration . what happenbs if they do something accidently wrong?
• you dont want this happenoj g on the physical system
• Virtualization can reduce the amount of hardware needed for the necessary training environments
• allows for almost instant restoration of the training environment by using undo disks and differencing disks to discard changes made by a trainee
• multiple VMs allow for different learning environments to be running simultaneously on the same hardware

Help desks

• help desks must support several varities of hardware and softawre configurations . the combination of multiple windows versions and various applications becomes unwieldy
• help desk personnel must maintain multiple computers or restart their computers or restart their computers to support people who use various configuartions . they might not even have access to a configuration that a customer is using , and so trhey must guess of fly blind with their assistance . customer satisfaction can suffer under these scenarios
• using virtaulaizaztion , help desks are better able to duplicate users' environment , including the os and applications ,
• help dewsk personnel using Vista can support previous windows OS by simply starting a prebuilt VM from a saved state which takeds only seconds

ERP implementation

• multiple servers :
• application servers
• productionb server
• qualitty server
• could be installed in one physical server
• SAP ERP could be virtualizdd and sizing takes place

V VS CC

• VIRTUALIZATION IS A SOFTWARE THAT MANIPULATES H/W
• cc refers to a service that results from this manipulation
• Virtualization is a fundemental element of cloud computing and helps deliver on the value of cloud computing