INTRODUCTION
TO
VIRTUALIZATION
KRISTEN WILLIAMS
MOSES IKE
OBJECTIVES
•Virtual machine definition
• Common terminology
• Virtualization Software
• Common Virtualization File types
• Snapshots
•Uses of Virtualization
• Lab: Installing and Configuring a VM
WHAT IS A VIRTUAL MACHINE ?
A virtual machine (VM) is a software
implementation of a machine (e.g., a
computer) that executes programs like a
physical machine.
• System Virtual Machine
• Process Virtual Machine (Containers)
BEFORE AND AFTER
VIRTUALIZATION
SYSTEM AND PROCESS
VIRTUALIZATION
• A system virtual machine provides a
complete system platform which supports
the execution of a complete operating
system (OS).
• A process virtual machine is designed to run
a single program, which means that it
supports a single process. E.g. A safe
browser, or File Opener
COMMON TERMINOLOGIES
• Virtual Machine - A representation of a real machine using
software that provides an operating environment which can
run or host a guest operating system.
• Guest Operating System - An operating system running in a
virtual machine environment that would otherwise run directly
on a separate physical system.
• Host Operating System - A computer OS that has one or
more virtual machines running is defined as a host OS.
• Virtual Machine Monitor - Software that runs in a layer
between a hypervisor or host operating system and one or
more virtual machines that provides the virtual machine
abstraction to the guest operating systems.
• Hypervisor – Same or Similar as Virtual Machine Monitor
COMMON TERMINOLOGIES
• Hosted Virtualization - A virtualization approach where
virtualization services run on top of a standard operating
system (the host). In this approach, the virtualization software
relies on the host operating system to provide the API to talk
directly to the underlying hardware. (Virtual Box Guest
Additions)
• Para-Virtualization - A virtualization approach that exports a
modified hardware abstraction, which requires operating
systems to be explicitly modified and ported to run.
• Virtualization Hardware Support- Industry standard to
provide hardware support for virtualization. E.g. processor
extensions to address CPU and some memory virtualization.
Future support will include I/O virtualization
• Hardware-level Virtualization (Bare Metal) - Virtualization
layer sits right on top of the hardware. No Host Operating
System, just the hypervisor running the VMs
VIRTAULIZATION SOFTWARE
VMware: The most popular virtualization software vendor in terms
of range of offerings, market share.
Example: VMware Workstation/Player, VMware Vsphere, VCenter
VIRTAULIZATION SOFTWARE
Microsoft: Microsoft provides a lot of free virtualization resources
and tools, such as Hyper V, Microsoft Virtual Server and Virtual
PC. Keep in mind, however, that Virtual Software and Virtual PC
can only work with Windows guests and hosts, meaning they are
not viable options for those who want to run Linux or Mac
operating systems.
Citrix: Citrix, after acquiring the company that created and
licensed the open-source virtualization package Xen, has become
a major player in the field of virtualization.
Parrallels: Best known for its Desktop for Mac, the first
commercial virtualization product that could run on Mac OS hosts
VIRTAULIZATION SOFTWARE
Virtual Box: Its FREE !! From Oracle. VirtualBox is the most
popular package and supports a variety of guest and host
systems.
COMMON
VIRTULAIZATION FILE TYPES
*.vmdk – Virtual disk files that the Hypervisor uses to
simulate the hard drive for your virtual system. There
may be one or more of these files associated with a
single VM
*.vmx - Files ending in “.vmx” are VMware
configuration files. These files contain details such as
the type of hardware to simulate for the virtual system,
the amount of memory to allow the virtual machine to
use, and so on.
*.nvram - This file stores the state of the virtual
machine's BIOS.
*.ova – Format for an exported or imported VM
Appliance
SNAPSHOTS
• A snapshot preserves the state and data of a virtual
machine at a specific point in time. You can take a
snapshot while a virtual machine is powered on,
powered off or suspended.
• The snapshot captures the entire state of the virtual
machine at the time you take the snapshot.
WHAT IS CAPTURED BY A
SNAPSHOT ?
• The state of all the virtual machine's disks. (for
example: powered-on, powered-off,
suspended).The contents of the virtual machine's
memory. The data includes all of the files that make
up the virtual machine.
• This includes disks, memory, and other devices,
such as virtual network interface cards.
• The virtual machine settings.
WAYS OF USING SNAPSHOTS
• Making Risky Changes: If you plan to make risky
changes in a virtual machine (for example, testing new
software or examining a virus), take a snapshot before
you begin to make those risky changes. If you
encounter a problem, click Revert to return the virtual
machine to its state at the time you took the snapshot.
• Starting a Virtual Machine Repeatedly in the Same
State: You can configure the virtual machine to revert
to the snapshot any time it is powered off.
USES OF VIRTUALIZATION
Running Old Apps: Got an application that won't play nice
with Windows 8,7 or Vista but works fine in XP
Access Virus-Infected Data: You were sent a file that
your antivirus program has flagged but which contains
important data you just have to view
Browse Safely: Curious to visit a malware site, and play
around
Test Software, Upgrades, or New Configurations: You
could use your virtual computer to test new software,
updates, or even new configurations of software before
deployment in production. Cloning existing production
systems and testing or developing them in a virtualized
environment.
USES OF VIRTUALIZATION
No More need to Dual Boot: Run Windows on Mac,
Linux, or vice versa
Back Up an Entire Operating System: Because the
virtual OS is entirely contained within a series of files,
backing it up is as simple as backing up any other files.
Reuse Old Hardware: By installing Citrix Xen Desktop
on a server, you can turn old, less powerful computers
into thin clients.
Go green!: You might have a few servers in your
environment that aren’t being fully utilized. Condense
them as virtual machines on a single physical server.
USES OF VIRTUALIZATION
Backup and recovery: Because your virtual server is
just a single system file, you can easily create a
backup copy of your entire VM. So if things go wrong,
just scrap the whole VM and reload the saved backup
copy.
Training: Use virtual machines to train your IT staff,
without the worry that they’ll irreversibly break
something.
VM Migration: Hardware Independence. Migrate VMs
from one hardware to another, with no loss in
downtime
QUESTIONS ?