Virtualization and how it leads to cloud...

- Huzefa Husain- https://in.linkedin.com/in/huzefaaa- huzefaaa@gmail.com

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Overview

• What exactly is virtualization?• Types of virtualization• Current trend in virtualization• How virtualization leads to Cloud Computing?• Cloud Computing Stack

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What exactly is virtualization? • Inserting a layer of software between the machine and

traditional operating systems. • Creating multiple logical server OS instances on one

physical piece of hardware• All HW drivers are virtualized. • Each virtual machine is completely independent of the others

and doesn't 'realize’ it’s virtualized.

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Types of Virtualization

Hosted Virtualization Bare-metal Virtualization

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What is a Hypervisor?• A hypervisor, also called a virtual machine manager (VMM),

is a program that allows multiple operating systems to share a single hardware host.

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It's all about Rings• x86 CPUs provide a range of protection levels also known as

rings in which code can execute. Ring 0 has the highest level privilege and is where the operating system kernel normally runs. Code executing in Ring 0 is said to be running in system space, kernel mode or supervisor mode. All other code such as applications running on the operating system operate in less privileged rings, typically Ring 3.

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Rings in virtualizationTraditional systems

• Operating system runs in privileged mode in Ring 0 and owns the hardware

• Applications run in Ring 3 with less privileges

Virtualized systems• VMM runs in privileged mode in Ring 0 • Guest OS inside VMs are fooled into thinking

they are running in Ring 0, privileged instructions are trapped and emulated by the VMM

• Newer CPUs (AMD-V/Intel-VT) use a new privilege level called Ring -1 for the VMM to reside allowing for better performance as the VMM no longer needs to fool the Guest OS that it is running in Ring 0.

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Example – Server Consolidation

3 – server scenario

Consolidated server

scenario

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Example – Server Consolidation

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Example – Server Consolidation

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The benefits of Going Virtual (The business perspective….. )

• Simplify data center – to create more dynamic and flexible IT Infrastructure

• Reliability and Availability - Build up business continuity through improved disaster recovery solutions and deliver high availability throughout the datacenter.

• Reduce capital expenses through server consolidation

• Improve operating expenses through automation.

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The benefits of Going Virtual (The technology

perspective….. )

• Efficiency: use the native hardware of the physical machine to as great a degree as possible (without affecting application Performance)

• Flexible Resource Allocation: Hot add vCPUs and memory, VMFS volume grow, hot extend virtual disks, hot add virtual disks, hot add NICs.

• Advanced Memory Management: Ability to reclaim unused memory, de-duplicate memory pages, compress memory pages

• Less administrative overhead: Single management interface to control hosts and VMs

Marketplace Offerings

Freely Available

• OpenVZ (Open Source)• KVM• VMWare Server (GSX)• Xen 3.0 (Open Source)

Commercial

• Virtuozzo• VMWare ESX• Xen Enterprise• Microsoft Virtual Server• Virtual Iron• RedHat Virtualization

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Virtualization options (Citrix Xen or Vmware ESXi)

• Xen and ESXi are two cost efficient mature technologies in market and are “enterprise ready”.

Citrix Xen: The virtualization technique is called integrated virtualization or paravirtualization.

VMware ESXi: The virtualization technique is called full virtualization.

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• Two main directions in virtualization:

– Full virtualization (ESXi): the VMM provides an identical abstraction of the underlying hardware

• No changes required to the guest Oss

– Paravirtualization (Xen): the VMM provides an “almost” identical abstraction of the underlying hardware. The abstraction implements some new instructions to make the machine virtualizable.

• Guest OSs need to be modified.

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Feature Comparison (Vmware ESXi Vs Citrix Xen)Hypervisor Attributes VMware vSphere Hypervisor 5.0 Citrix XenServer 5.6 FP1 

Small Disk Footprint Small disk footprint  >1GB

OS Independence  No reliance on general purpose operating system  Relies on Linux in Dom0 management Partition

Hardened Drivers  Optimized with hardware vendors  Generic Linux Drivers

Advanced Memory Management

 Ability to reclaim unused memory, de-duplicate memory pages, compress memory pages

 Only uses balloning. No ability to de-duplicate or compress pages. Does not adjust memory allocation based

on VM usage.

Advanced Storage Management

 VMware vStorage VMFS,Storage vMotion, Storage DRS 

 Lacks an integrated cluster file system, no live storage migration, storage features support very few

arrays

High I/O Scalability  Direct driver model  I/O bottleneck in Dom0 management OS

Host Resource Management

 Network traffic shaping, per-VM resource shares, set quality of service priorities for storage and

network I/O

 Lacks similar capabilities

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Feature Comparison (Vmware ESXi Vs Citrix Xen)

Hypervisor Attributes VMware vSphere Hypervisor 5.0 Citrix XenServer 5.6 FP1 

Performance Enhancements

 AMD RVI, Intel EPT large memory pages, universal 32-way vSMP, VMI paravirtualization, VMDirectPath I/O, PV guest SCSI

driver

 No large memory pages, no paravirt guest SCSI device, Requires inflexible SR-IOV

Virtual Security Technology

 VMware VMsafe™ Enables hypervisor level security introspection

 Nothing comparable

Flexible Resource Allocation

 Hot add VM vCPUs and memory, VMFS volume grow, hot extend virtual disks, hot add virtual disks

 Nothing comparable

Custom image creation and management

 VMware Image Builder allows administrators to create custom ESXi images for different types of deployment, such as ISO-based installation, PXE-based installation, and Auto Deploy.

 Nothing comparable

Auto Deploy  vSphere Auto Deploy enables faster provisioning of multiple hosts. New hosts are auto provisioned based on rules defined by

user.

 Nothing comparable

Management Interface Firewall

 ESXi Firewall is a service-oriented and stateless firewall that protects the ESXi 5.0 management interface. Configured using

the vSphere Client or at the command line with esxcli interfaces.

 Nothing comparable

Enhanced Virtual Hardware

 32-way virtual SMP, 1TB virtual machine RAM, Non hardware accelerated 3D graphics, USB 3.0 device support, Unified

Extended Firmware Interface (UEFI).

 8-way virtual SMP only, 32 GB RAM per virtual machine

VMWare Failover technology

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VMWare HAMinimize Downtime from Server and Operating System Failures

Data Center 1

Data Center 2

Fault Tolerance(Active – Shadow)

Local Survivability

Enterprise Survivability

Storage

Storage

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Current market trend in virtualization….(Source: Gartner)

Gartner Magic Quadrant

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Market Share

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Client desktop virtualization• According to Gartner:- Professional clients using HVD will

grow from approximately 368,000 in 2008 to 70 million in 2014.

- Professional users will migrate away from the traditional PC delivery model, driving HVD growth.

- By 2014, 10% of professional client install base will consist of thin clients and diskless / repurposed PCs, from 3% in 2008.

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Hypervisor comparison

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What is Cloud?

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Virtualization leads to Cloud Computing

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Cloud Computing Stack

Compute ComputeApp Framework

ComputeApp FrameworkBusiness Logic

• Amazon• GoGrid• Linode• Rackspace• Others…

• AppEngine• Azure• EngineYard• Force.com• Heroku

• Google Apps• Salesforce• Taleo,

Workday,• Many others

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Thank You