Cloud Computing

CSIW ZG527

Contributors & Designers of document content : Wipro Course Faculty Team

BITS Pilani
Pilani Campus
BITS Pilani, Pilani Campus
Cloud Computing

Disclaimer and Acknowledgement

• The content for these slides has been obtained from books and various other source on the Internet

• I here by acknowledge all the contributors for their material and inputs and gratefully acknowledge people others
who made their course materials freely available online.
• .I have provided source information wherever necessary

• Students are requested to refer to the textbook w.r.t detailed content of the presentation deck that is expected to

be shared over taxilla.

• The faculty team has modified the sourced content flow to suit the requirements of this WIMS section class

dynamics & for live lecture delivery flow for presentation.

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Notice from the Wipro Academic Team

 It is important to know that just login to the session does not guarantee the attendance.
 Once you join the session, continue till the end to consider you as present in the class.
 IMPORTANTLY, you need to make the class more interactive by responding to Professors queries
in the session.
 Whenever Professor calls your number / name ,you need to respond, otherwise it will be
considered as ABSENT

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Introduction to Virtualisation

• Content

Virtualisation

Introduction to Virtualization

Use & demerits of Virtualization

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Introduction to Virtualisation

Virtualization in the cloud - Transforming a Classic Data Center (CDC) into a Virtualized Data
Center

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 Virtualized Data Center

Virtualized Data Center (VDC)

Transforming a Classic Data Center (CDC) into a

Virtualized Data Center (VDC) requires
Virtualize Network
virtualizing the core elements of the data center.
Virtualize Storage

Virtualize Compute

Classic Data Center

(CDC)

Using a phased approach to a virtualized infrastructure

enables smoother transition to virtualize core elements.

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Compute Virtualization

Compute Virtualization

It is a technique of masking or abstracting the physical compute hardware

and enabling multiple operating systems (OSs) to run concurrently on a
single or clustered physical machine(s).

• Enables creation of multiple virtual machines (VMs), each running an

OS and application
• VM is a logical entity that looks and behaves like physical
machine

• Virtualization layer resides between hardware and VMs Virtualization Layer

• Also known as hypervisor
x86 Architecture

• VMs are provided with standardized hardware resources

NIC Card Memory Hard

CPU Disk

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Need for Compute Virtualization

Hypervisor
x86 Architecture x86 Architecture

NIC Card Memory Hard Disk CPU NIC Card Memory Hard Disk
CPU

Before Virtualization After Virtualization

• Runs single operating system (OS) per machine • Runs multiple operating systems (OSs) per
at a time machine concurrently
• Couples s/w and h/w tightly • Makes OS and applications h/w independent
• May create conflicts when multiple applications • Isolates VM from each other, hence no conflict
run on the same machine • Improves resource utilization
• Underutilizes resources • Offers flexible infrastructure at low cost
• Is inflexible and expensive
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Hypervisor

Hypervisor
It is a software that allows multiple operating systems (OSs) to run concurrently
on a physical machine and to interact directly with the physical hardware.

Has two components

– Kernel
VMM VMM VMM
– Virtual Machine Monitor (VMM) Hypervisor (Kernel and VMM)

x86 Architecture

NIC Card Memory Hard

CPU Disk

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Types of Hypervisor

APP

Hypervisor Hypervisor
x86 Architecture Operating System
x86 Architecture

CPU NIC Card Memory Hard Disk

CPU NIC Card Memory Hard Disk
Type 1: Bare-Metal Hypervisor
Type 2: Hosted Hypervisor

Type 1: Bare-Metal Hypervisor Type 2: Hosted Hypervisor

• It is an operating system (OS) • It installs and runs as an application
• It installs and runs on x86 bare-metal • It relies on operating system (OS) running on
hardware physical machine for device support and physical
• It requires certified hardware resource management

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Benefits of Compute Virtualization

Server consolidation

Isolation

Encapsulation

Hardware independence

Reduced cost

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Requirements: x86 Hardware Virtualization

An operating system (OS) is designed to run on a bare-metal hardware and to fully own
the hardware
– x86 architecture offer four levels of privilege
Ring User Apps
• Ring 0, 1, 2, and 3
3
• User applications run in Ring 3 Ring
• OS run in Ring 0 (most privileged) 2
Ring
Challenges of virtualizing x86 hardware 1
Ring OS
– Requires placing the virtualization layer below the OS layer 0
– Is difficult to capture and translate privileged OS instructions at runtime
X86 Hardware

• Techniques to virtualize compute

– Full, Para, and hardware assisted virtualization

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Full Virtualization

Virtual Machine Monitor (VMM) runs in the privileged Ring 0

VMM decouples guest operating system (OS) from the underlying physical hardware Ring User Apps
3
Each VM is assigned a VMM Ring
2
– Provides virtual components to each VM Ring Guest OS
1
– Performs Binary Translation (BT) of non-virtualizable OS instructions Ring Hypervisor
0
Guest OS is not aware of being virtualized Physical Machine
X86 Hardware

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Para virtualization

Guest operating system (OS) knows that it is virtualized Ring User Apps
3
Ring
Guest OS runs in Ring 0
2
Ring
Modified guest OS kernel is used, such as Linux and OpenBSD 1 Paravirtualized
Ring Guest OS
0
Unmodified guest OS is not supported, such as Microsoft Windows Hypervisor

Physical Machine
X86 Hardware

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Hardware Assisted Virtualization

Achieved by using hypervisor-aware CPU to handle privileged instructions Ring 3 User Apps

Ring 2
– Reduces virtualization overhead caused due to full and paravirtualization
Ring 1
– CPU and Memory virtualization support is provided in hardware
Ring 0 Guest OS
Enabled by AMD-V and Intel VT technologies in the x86 processor architecture
VMM

Physical Machine
X86 Hardware

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Virtual Machine

From a user’s perspective, a logical compute system

– Runs an operating system (OS) and application like a physical

machine

Hypervisor
– Contains virtual components such as CPU, RAM, disk, and NIC x86 Architecture

From a hypervisor’s perspective CPU NIC Card Memory Hard Disk

– Virtual machine (VM) is a discrete set of files such as configuration

file, virtual disk files, virtual BIOS file, VM swap file, and log file

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Virtual Machine Files

File name Description

Virtual BIOS File • Stores the state of the virtual machine’s (VM’s) BIOS
• Is a VM’s paging file which backs up the VM RAM contents
Virtual Swap File
• The file exists only when VM is running
• Stores the contents of the VM’s disk drive
Virtual Disk File • Appears like a physical disk drive to VM
• VM can have multiple disk drives
• Keeps a log of VM activity
Log File
• Is useful for troubleshooting
• Stores the configuration information chosen during VM creation
Virtual Configuration File • Includes information such as number of CPUs, memory, number and type
of network adaptors, and disk types

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File System to Manage VM Files

The file systems supported by hypervisor are Virtual Machine File System (VMFS) and Network File System
(NFS)

VMFS
– Is a cluster file system that allows multiple physical machines to perform read/write on the same storage
device concurrently
– Is deployed on FC and iSCSI storage apart from local storage

NFS
– Enables storing VM files on a remote file server (NAS device)
– NFS client is built into hypervisor

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Virtual Machine Hardware

Parallel Serial/Com USB controller

port ports and USB devices

IDE controllers Floppy controller

and floppy drives

Graphic card Virtual Machine

Mouse

RAM

Keyboard

VM chipset with one Network adapters

or more CPUs SCSI controllers (NIC and HBA)

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VM Hardware Components

Virtual Hardware Description

• Virtual machine (VM) can be configured with one or more virtual CPUs
vCPU
• Number of CPUs allocated to a VM can be changed

• Amount of memory presented to the guest operating system (OS)

vRAM
• Memory size can be changed based on requirement
• Stores VM's OS and application data
Virtual Disk
• A VM should have at least one virtual disk
vNIC • Enables a VM to connect to other physical and virtual machines

Virtual DVD/CD-ROM Drive • It maps a VM’s DVD/CD-ROM drive to either a physical drive or an .iso file

Virtual Floppy Drive • It maps a VM’s floppy drive to either a physical drive or an .flp file
Virtual SCSI Controller • VM uses virtual SCSI controller to access virtual disk
Virtual USB Controller • Maps VM’s USB controller to the physical USB controller
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Virtual Machine Console

Provides mouse, keyboard, and screen functionality

Sends power changes (on/off) to the virtual machine (VM)

Allows access to BIOS of the VM

Typically used for virtual hardware configuration and troubleshooting issues

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Resource Management

Resource management

A process of allocating resources from physical machine or clustered physical machines

to virtual machines (VMs) to optimize the utilization of resources.

Goals of resource management

– Controls utilization of resources

– Prevents VMs from monopolizing resources

– Allocates resources based on relative priority of VMs

Resources must be pooled to manage them centrally

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Resource Pool

Resource pool

It is a logical abstraction of aggregated physical resources that are managed centrally.

Created from a physical machine or cluster

Administrators may create child resource pool or virtual machine (VM) from the parent resource pool

Reservation, limit, and share are used to control the resources consumed by resource pools or VMs

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Resource Pool Example

Standalone Physical Machine – Machine 1

Parent Pool
CPU = 3000 MHz
Memory = 6GB

Engineering Pool (Child Pool) Finance Pool (Child Pool)

Marketing-Production VM

CPU = 1000 MHz CPU = 1000 MHz CPU = 500 MHz

Memory = 2GB Memory = 2GB Memory = 1GB

Engineering-Test VM Engineering-Production Finance-Test VM Finance-Production VM

VM
CPU = 500 MHz CPU = 500 MHz CPU = 500 MHz CPU = 500 MHz
Memory = 1GB Memory = 1GB Memory = 1GB Memory = 1GB

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Share, Limit, and Reservation

Parameters that control the resources consumed by a child resource pool or a virtual machine (VM) are as
follows:

– Share
• Amount of CPU or memory resources a VM or a child resource pool can have with respect to its
parent’s total resources

– Limit
• Maximum amount of CPU and memory a VM or a child resource pool can consume

– Reservation
• Amount of CPU and memory reserved for a VM or a child resource pool

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Optimizing CPU Resources

Modern CPUs are equipped with multiple cores and hyper-threading

– Multi-core processors have multiple processing units (cores) in a single CPU
– Hyper-threading makes a physical CPU appear as two or more logical CPUs

Allocating a CPU resource efficiently and fairly is critical

Hypervisor schedules virtual CPUs on the physical CPUs

Hypervisors support multi-core, hyper-threading, and CPU load-balancing features to optimize CPU
resources

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Multi-core Processors

VM with VM with VM with

one CPU two CPUs four CPUs

Virtual CPU

Virtual
Physical

Thread Thread Thread Thread Thread Thread Thread Thread

Thread

Core

Socket

Single – core Dual – core Quad – core

Dual – socket system Single – socket system Single – socket system

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Hyper-threading

Makes a physical CPU appear as two Logical CPUs (LCPUs) VM with VM with VM with
one CPU two CPUs one CPU
– Enables operating system (OS) to schedule two or more threads
simultaneously

Two LCPUs share the same physical resources

– While the current thread is stalled, CPU can execute another
thread

Hypervisor running on a hyper-threading-enabled CPU provides

improved performance and utilization LCP LCP
U U

LCP LCP
U U

Thread 1 and 2 Dual – core Thread 1 and 2

Single – socket system
with hyperthreading

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Optimizing Memory Resource

Hypervisor manages a machine’s physical memory

– Part of this memory is used by the hypervisor
– Rest is available for virtual machines (VMs)

VMs can be configured with more memory than physically available, called ‘memory overcommitment’

– Memory optimization is done to allow overcommitment

Memory management techniques are Transparent page sharing, memory ballooning, and memory
swapping

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Memory Ballooning

No memory shortage, balloon

remains un-inflated

Virtual Machine (VM) 1. Memory shortage, balloon inflates

2. Driver demands memory from guest
operating system (OS)
3. Guest OS forces page out
4. Hypervisor reclaims memory

Virtual Machine (VM)

1. Memory shortage resolved,

deflates balloon
2. Driver relinquishes memory
3. Guest OS can use pages
4. Hypervisor grants memory Virtual Machine (VM)

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Memory Swapping

Each powered-on virtual machine (VM) needs its own swap file
– Created when the VM is powered-on
– Deleted when the VM is powered-off

Swap file size is equal to the difference between the memory limit and the VM memory reservation

Hypervisor swaps out the VM’s memory content if memory is scarce

Swapping is the last option because it causes notable performance impact

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Physical to Virtual Machine (P2V) Conversion

P2V Conversion
It is a process through which physical machines are converted into virtual machines (VMs).

Clones data from physical machine’s disk to VM disk

Performs system reconfiguration of the destination VM such as:

– Change IP address and computer name
– Install required device drivers to enable the VM to boot
Conversion

Physical Machine Virtual Machine (VM)

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Benefits of P2V Converter

Reduces time needed to setup new virtual machine (VM)

Enables migration of legacy machine to a new hardware without reinstalling operating

system (OS) or application

Performs migration across heterogeneous hardware

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Components of P2V Converter

There are three key components:

– Converter server
• Is responsible for controlling conversion process
• Is used for hot conversion only (when source is running its OS)
• Pushes and installs agent on the source machine
– Converter agent
• Is responsible for performing the conversion
• Is used in hot mode only
• Is installed on physical machine to convert it to virtual machine (VM)
– Converter Boot CD
• Bootable CD contains its operating system (OS) and converter application
• Converter application is used to perform cold conversion

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Conversion Options

Hot conversion
– Occurs while physical machine is running
– Performs synchronization
• Copies blocks that were changed during the initial cloning period
– Performs power off at source and power on at target virtual machine (VM)
– Changes IP address and machine name of the selected machine, if both machines must co-exist on the
same network

Cold conversion
– Occurs while physical machine is not running OS and application
– Boots the physical machine using converter boot CD
– Creates consistent copy of the physical machine

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Hot Conversion Process

Converter server
running converter
software

Step 1: Converter
server installs agent on Step 3: Creates VM
source physical on destination
machine machine

Agent

Step 4: Clones
source disk to VM
Powered-on disk
Source Physical Source
Snapshot
Machine Volume

Snapshot Destination Physical

Machine running
Step 2: Agent takes hypervisor
snapshot of source
volume
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Hot Conversion Process (contd.)

Converter server
running converter
software

Step 6: VM is ready to run

Step 5: Synchronizes
and reconfigures the
VM

Reconfiguration
Agent

Powered-on
Source Physical Source
Snapshot
Machine Volume

Snapshot Destination Physical

Machine running
hypervisor

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Cold Conversion Process

Step 1: Boot physical Step 2: Creates VM

machine with converter on destination
boot CD machine
Converter boot CD

Powered-on
Source Physical Source
Volume
Machine

Destination Physical
Machine (Running
Hypervisor)

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Cold Conversion Process (contd.)

Step 4: Installs required drivers Step 5: VM is ready to run

to allow OS to boot on VM

Converter boot CD

Reconfiguration

Powered-on
Source Physical Source Step 3: Clones
Machine Volume source disk to VM
disk
Destination Physical
Machine (Running
Hypervisor)

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Storage Virtualization

Storage virtualization

It is the process of masking the underlying complexity of physical storage resources and
presenting the logical view of these resources to compute systems.

Logical to physical storage mapping is performed by virtualization layer

Virtualization layer abstracts the identity of physical storage devices

– Creates a storage pool from multiple, heterogeneous storage arrays

Virtual volumes are created from the storage pools and are assigned to the compute system

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Benefits of Storage Virtualization

• Adds or removes storage without any downtime

• Increases storage utilization thereby reducing TCO

• Provides non-disruptive data migration between storage devices

• Supports heterogeneous, multi-vendor storage platforms

• Simplifies storage management

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Storage Virtualization at Different Layers

Layers Examples

Compute • Storage provisioning for VMs

• Block-level virtualization
Network
• File-level virtualization

• Virtual Provisioning
Storage
• Automated Storage Tiering

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Storage for Virtual Machines

Compute Compute
VMs are stored as set of files on storage space available to hypervisor 1 2

‘Virtual disk file’ represents a virtual disk used by a VM to store its data VM VM
3 4

Size of virtual disk file represents storage space allocated to virtual disk
Virtual Virtual Virtual Virtual
VMs remain unaware of disk file disk file disk file disk file

VMF NF
– Total space available to the hypervisor S S
– Underlying storage technologies
FC IP
SAN Network

FC iSC NA
Storage SI BITS Pilani, Pilani Campus
S
File System for Managing VM Files

Hypervisor uses two file systems to manage the VM files

– Hypervisor’s native file system called Virtual Machine File System (VMFS)

– Network File System (NFS) such as NAS file system

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Network Virtualization

Network Virtualization

It is a process of logically segmenting or grouping physical network(s) and making them operate as
single or multiple independent network(s) called “Virtual Network(s)”.

Enables virtual networks to share network resources

Allows communication between nodes in a virtual network without routing of frames
Enforces routing for communication between virtual networks

Restricts management traffic, including ‘Network Broadcast’, from propagating to other virtual network
Enables functional grouping of nodes in a virtual network

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Network Virtualization in VDC

Involves virtualizing physical and VM networks Physical Server Physical Server

Physical Network
Hypervisor Hypervisor

• Consists of following physical components:

 Network adapters, switches, routers, bridges,
PNIC PNIC

repeaters, and hubs

• Provides connectivity
Physical
 Among physical servers running hypervisor Network
 Between physical servers and clients
Client
 Between physical servers and storage systems

PNIC – Physical NIC

Storage Array

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Benefits of Network Virtualization

Benefit Description
• Restricts access to nodes in a virtual network from another virtual
Enhances security network
• Isolates sensitive data from one virtual network to another
• Restricts network broadcast and improves virtual network
Enhances performance
performance
• Allows configuring virtual networks from a centralized
Improves manageability management workstation using management software
• Eases grouping and regrouping of nodes
• Enables multiple virtual networks to share the same physical
Improves utilization and network, which improves utilization of network resource
reduces CAPEX • Reduces the requirement to setup separate physical networks for
different node groups

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Components of VDC Network Infrastructure
• VDC network infrastructure includes both virtual and physical network components
 Components are connected to each other to enable network traffic flow

Component Description
• Connects VMs to the VM network
Virtual NIC
• Sends/receives VM traffic to/from VM network
Virtual HBA • Enables a VM to access FC RDM disk/LUN assigned to the VM
• Is an Ethernet switch that forms VM network
• Provides connection to virtual NICs and forwards VM traffic
Virtual switch
• Provides connection to hypervisor kernel and directs hypervisor traffic:
management, storage, VM migration
Physical adapter: NIC, • Connects physical servers to physical network
HBA, CNA • Forwards VM and hypervisor traffic to/from physical network
• Forms physical network that supports Ethernet/FC/iSCSI/FCoE
Physical switch, router • Provides connections among physical servers, between physical servers and
storage systems, and between physical servers and clients

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Virtual Network Component: Virtual NIC

Connects VMs to virtual switch

Forwards Ethernet frames to virtual switch

Has unique MAC and IP addresses

Supports Ethernet standards similar to physical NIC

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Overview of Desktop and Application Virtualization

Tight dependency Virtualization breaks dependencies

between the layers between the layers

User State (data and settings)

Application
Application Virtualization
Isolate the application from OS and hardware

Operating System
Desktop Virtualization
Isolate hardware from OS, application and
user state
Hardware

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 Desktop Virtualization

Desktop Virtualization

Technology which enables detachment of the user state, the Operating

System (OS), and the applications from endpoint devices.

• Enables organizations to host and centrally manage desktops

• Desktops run as virtual machines within the VDC

• They may be accessed over LAN/WAN

• Endpoint devices may be thin clients or PCs

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Benefits of Desktop Virtualization

Enablement of thin clients

Improved data security

Simplified data backup

Simplified PC maintenance

Flexibility of access

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Desktop Virtualization Techniques

Technique 1: Remote Desktop Services(RDS)

Technique 2: Virtual Desktop Infrastructure (VDI)

Desktop virtualization techniques provide ability to centrally host and manage desktop environments

– Deliver them remotely to the user’s endpoint devices

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Remote Desktop Services

• RDS is traditionally known as terminal services

• A terminal service runs on top of a Windows installation

 Provides individual sessions to client systems

 Clients receive visuals of the desktop

 Resource consumption takes place on the server

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Benefits of Remote Desktop Services

Rapid application delivery

– Applications are installed on the server and accessed from there

Improved security

– Applications and data are stored in the server

Centralized management

Low-cost technology when compared to VDI

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Virtual Desktop Infrastructure(VDI)

• VDI involves hosting desktop which runs as VM on the server in the VDC

 Each desktop has its own OS and applications installed

• User has full access to resources of virtualized desktop

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VDI: Components

VM execution
Endpoint devices server

• Endpoint devices
Connection
• VM hosting/execution servers broker Shared
Storage

• Connection Broker
PCs,
notebooks
thin clients

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How does this work?

Server (HW1.js)
Server
require('http');
http.createServer
(…)

Internet Amazon SimpleDB

Web page (home.ejs)
<html><head>
<body>…
DOM
accesses
function foo() {
$("#id").html("x");
}
Browser
Script (app.js)

Your VM

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Use case Scenario for virtualization

Cust 1

Cust 2
Admin
Physical machine
Suppose Admin has a machine with 4 CPUs and 8 GB of memory, and three customers:
– Cust 1 wants a machine with 1 CPU and 3GB of memory
– Cust 2 wants 2 CPUs and 1GB of memory
– Cust 3 wants 1 CPU and 4GB of memory
What should Admin do?

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Resource allocation in virtualization

Cust 1
Virtual
machine
monitor Cust 2
Admin
Physical machine
Virtual machines Cust 3

Admin can sell each customer a virtual machine (VM) with the requested resources
– From each customer's perspective, it appears as if they had a physical machine all by themselves
(isolation)

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How does it work?

Ap VM 2
VM Virt Phys
p Ap
1 0-99 0-99
Ap
1 299-399 100-199
p p
2 0-99 300-399 OS 1 OS 2
2 200-299 500-599
2 600-699 400-499
VMM
Translation table
Physical machine

Resources (CPU, memory, ...) are virtualized

– VMM ("Hypervisor") has translation tables that map requests for virtual resources to physical resources
– Example: VM 1 accesses memory cell #323; VMM maps this to memory cell 123.
– For which resources does this (not) work?
– How do VMMs differ from OS kernels?

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Benefit: Migration in case of disaster

Cust 1
Virtual
machine
Admin monitor
Cust 2

Virtual machines Cust 3

What if the machine needs to be shut down?
Physical machines
– e.g., for maintenance, consolidation, ...
– Admin can migrate the VMs to different physical machines without any customers noticing

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Benefit: Time sharing

Cust 4

Cust 1
Virtual
machine
monitor
Cust 2
Admin
Physical machine
What if Admin gets another customer?
Virtual machines Cust 3
– Multiple VMs can time-share the existing resources
– Result: Admin has more virtual CPUs and virtual memory than physical resources (but not all can be active
at the same time)

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Benefit and challenge: Isolation

Cust 4

Cust 1
VMM

Cust 2
Admin
Physical machine
Virtual machines Cust 3
Good: Cust 4 can't access Cust 3’s data
Bad: What if the load suddenly increases?
– Example: Cust 4 VM shares CPUs with Cust 3's VM, and Cust 3 suddenly starts a large compute job
– Cust 4 performance may decrease as a result
– VMM can move Cust 4 's software to a different CPU, or migrate it to a different machine

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Recap: Virtualization in the cloud

Gives cloud provider a lot of flexibility

– Can produce VMs with different capabilities
– Can migrate VMs if necessary (e.g., for maintenance)
– Can increase load by overcommitting resources
Provides security and isolation
– Programs in one VM cannot influence programs in another
Convenient for users
– Complete control over the virtual 'hardware' (can install own operating system own applications, ...)
But: Performance may be hard to predict
– Load changes in other VMs on the same physical machine may affect the performance seen by the
customer

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Virtualization in the cloud - DEMO

Type -2 Hypervisor
Windows Sandbox – Light weight virtual Machine isolated, temporary virtual environment
Hyper-V Hyper-V virtual machines, Hypervisor on windows platform for virtualisation

Type -2 Hypervisor
Oracle Virtual Box
Ubuntu 22.04 LTS Jammy Jellyfish – With KVM Virtualization Running a Debian Distro inside it with VMM-
for live monitoring - Nested Paging, KVM Paravirtualization.
Ubuntu 23.04 Lunar Lobster to save the state of the virtual machines -Nested Paging,, KVM
Paravirtualization.
Storage Virtualisation – Oracle Database 23c VM appliance for data persistence Nested Paging, PAE/NX,
KVM Paravirtualization.

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Text and References

T1 Mastering Cloud Computing: Foundations and Applications Programming

Rajkumar Buyya, Christian Vecchiola, S.Thamarai Selvi

R1 Moving To The Cloud: Developing Apps in the New World of Cloud Computing 1st
Edition
by Dinkar Sitaram (Author), Geetha Manjunath (Author)

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BITS Pilani, Pilani Campus