Selecting the Correct HypervisorBoston Virtualization Deep Dive Day 2011Tim Mackey XenServer Evangelist

• Balanced representation of each hypervisor

• Where the sweet spots are for each vendor

• No discussion of performance

• No discussion of ROI and TCO

• What you should be thinking of with cloud

What to Expect Today ….

• Virtualization meant mainframe/mini

• x86 was “real mode”

• Until 1986 and the 80386DX changed the world• Now “protected mode” and rings of execution (typically ring 0 and ring 3)

• Real mode OS vs. Protected mode• x86 always boots to real mode (even today)• Kernel takes power on and enables protection models• Early kernels performed poorly in protected mode• Focus was on application virtualization not OS virtualization

The Land Before Time …

• Early 2001 ESX released as first type-1 for x86

• ESX uses an emulation model known as “binary translation” to trap protected mode operations and execute protected operations cleanly in the VMkernel• Heavily tuned over years of experience• Leverages 80386 protection rings and exception handlers• Can result in FASTER code execution

VMware Creates Mainstream x86 Virtualization

• 2005-2006 Intel and AMD introduce hardware assist• Idea was to take non-trappable privileged CPU OP codes and isolate them• Introduced “user mode” and “kernel mode”• Introduced “Ring -1”• Binary translation could still be faster

• 2008-2009 Intel and AMD introduce memory assist• CPU Op code only addressed part of the problem• Memory paging seen as key to future performance

• Hardware + Moore’s Law > Software + Tuning

Enter Hardware Assist

• Shared IO bottlenecks• VM density magnifies problem• Throughput demands impact peer VMs

• Enter SR-IOV in 2010• Hardware is virtualized in hardware• Virtual Function presented to guest

What About IO?

The Core Architectures

• ESX• VMkernel provides hypervisor• Service console is for management• IO is managed through emulated devices

• ESX is EOL long live ESXi• Service console is gone• Management via API/CLI• VMkernel now includes management,

agents and support consoles• Security vastly improved over ESX

vSphere Hypervisor

• Based on Open Source Xen

• Requires hardware assist

• Management through Linux control domain (dom0)

• IO managed using split drivers

XenServer

• Requires hardware assist

• Management through Windows 2008 “Parent partition”

• VMs run as child partitions

• Linux enabled using “Xenified” kernels

• IO is managed through parent partition and enlightened drivers

Hyper-V

• Requires hardware assist

• KVM modules part of Linux kernel

• Converts Linux into type-1

• Each VM is a process• Defined as “guest mode”

• IO managed via Linux and VirtIO

KVM

Commercial Free Contenders for Your Budget

VMware vSphere Hypervisor (ESXi)

•Single server management via vSphere client

Manageability•25

6 GB Host RAM

•2 physical cores

Scalability

•Thin provisioning

Key Features

•Very broad OS support

Guest Support

•Edition and feature based licensing

•Support a percentage of sale

Costs

Microsoft Hyper-V Server R2 SP1

•Single server management via Remote Server Admin Tools

Manageability•1T

B host RAM

•8 Logical CPUs per host

Scalability

•Host clustering

•Live migration

Key Features

•Windows Vista and Windows Server 2003 and higher

•RHEL 5.2 and SLES 10 and higher

Guest Support

•Edition and VM based pricing

•Support and SA extra

Costs

Red Hat Enterprise Virtualization (KVM)

•Centralized multi-server management

•Resource pools

Manageability

•1TB host RAM – 256 GB guest RAM

•96 Logical CPUs per host – 16 vCPUs per guest

Scalability

•All RHEL 5 devices and storage types

•Memory overcommit (KSM)

Key Features

•Windows XP and Windows Server 2003 and higher

•RHEL 3 and higher

Guest Support

•Annual support options priced per six sockets

Costs

Oracle VM

•Centralized multi-server management

•Resource pools

Manageability

•1TB host RAM – 32 GB guest RAM

•128 Logical CPUs per host – 32 vCPUs per guest

Scalability

•Secure live migration using shared storage (NFS, OCFS32 iSCSI)

•Load balancing and Cluster High Availability

Key Features

•Windows 2000 and higher

•Oracle Linux, RHEL

Guest Support

•Annual per host support options priced per socket

Costs

•Centralized multi-server management

•Resource pools

Manageability

•512 GB host RAM – 128 GB guest RAM

•64 logical CPUs per host – 16 vCPUs per guest

Scalability

•Live migration using shared storage (NFS, iSCSI, Fiber)

•VM snapshot and revert

Key Features

•Windows XP and higher

•CentOS, Debian,Oracle, SuSE, RHEL

Guest Support

•Edition based per host licensing

•Support is incident based

Costs

Citrix XenServer

Hypervisor is now a commodity!!

• Single hypervisor model is flawed• Wasted dollars, wasted performance

• Spend your resources where you need to• OS compatibility• VM density• IO performance• Application support models• Application availability

Maximizing Your Budget

Deconstructing Key Functionality

• Objective: Increase VM density and efficiently use host RAM

• Risks: Performance and Security

• Options: Ballooning, Page sharing, Compression, Swap

Memory Over Commit

Ballooning Method Page sharing Compression Performance/Security

vSphere 4.1 •Starts large•Windows and Linux

4k pages only with hash; latent coalesce with CoW

Compression of memory during oversubscribe

•Hash collisions•Recovery from swap•Compatible page scans

XenServer 5.6 •Starts large•Windows and Linux

None None •Doesn’t resize up

Hyper-V SP1 •Starts small•Windows only

None None •Memory space growth

RHEV (KVM) •Linux only Kernel Samepage Merging; CoW

None •B-tree collisions•Can use swap

• Objective: Ensure optimal performance of guests and hosts

• Risks: Performance and Security

• Options: Input metrics, reporting, variable usage models

Load Balancing

Feature name Input metrics Reporting Control points

vSphere 4.1 Dynamic Resource Scheduling

•CPU•Memory

None •Host affinity/anti-affinity•Initial placement 100%

XenServer 5.6 Workload Balancing •CPU•Memory•Disk IO R/W•Network IO R/W

•Pool/Host•VM•Audit

•Consolidation•Schedulable•Historical placement

Hyper-V R2 PRO (SCVMM) •CPU•Memory

SCVMM + SCOM •Initial placement 100%

RHEV (KVM) Load Balancing None None N/A

• Objective: Support data center and cloud networking

• Risks: Data leakage and performance

• Requirement: Make server virtualization compatible with networking

Virtual Networking

Feature name Key features Reporting Dependencies

vSphere 4.1 Virtual Distributed Switch

•Centralized management•Full Cisco Nexus features

NetFlow v9 Cisco Nexus 1000V

XenServer 5.6 FP1 Distributed Virtual Switch

•Centralized management•RSPAN•QoS•ACLs

NetFlow v5 None

Hyper-V R2 Windows network stack N/A N/A N/A

RHEV (KVM) Linux bridge N/A N/A N/A

The Sweet Spots

Key play: Legacy server virtualization• Large operating system support• Large eco-system => experienced talent readily available

Bonus opportunities• Feature rich data center requirements• Cloud consolidation through Cisco Nexus 1000V

Weaknesses• Complex licensing model• Reliance on SQL Server management database

VMware vSphere 4.1

Key play: Desktop virtualization• VM density is key• Memory over commit + deep understanding of Windows 7 => success

Bonus opportunities • Microsoft Server software• Ease of management for System Center customers

Weaknesses• Complex desktop virtualization licensing model• Complex setup at scale• “Patch Tuesday” reputation

Microsoft Hyper-V R2 SP1

Key plays: Linux virtualization• RHEL data centers

Weaknesses• Limited enterprise level feature set • Niche deployments and early adopter syndrome • Support only model may limit feature set

RedHat KVM

Key play: Hosted Oracle Applications• Oracle only supports its products on OVM

Bonus opportunities• Server virtualization • Applications requiring application level high availability• Data centers requiring secure VM motion

Weaknesses• Limited penetration outside of Oracle application suite• Support only model may limit future development

Oracle VM

Key play: Cloud platforms• Largest public cloud deployments

Bonus opportunities• Citrix infrastructure• Linux data centers• General purpose virtualization• Windows XP/Vista desktop virtualization

Weaknesses• Application support statements• HCL gaps

Citrix XenServer 5.6 FP1

Beyond the Data Center and into the Cloud

Hybrid Cloud• On premise• High fixed cost• Full control• Known security

• On/off premise• Low utility cost• Self-service• Fully elastic• Trusted security• Corporate control

• Off premise• Low utility cost• Self-service• Fully elastic

TraditionalDatacenter Public

Cloud

Hybrid Cloud

Hybrid Cloud

• On premise• High fixed cost• Full control• Known security

• On/off premise• Low utility cost• Self-service• Fully elastic• Trusted security• Corporate control

• Off premise• Low utility cost• Self-service• Fully elastic

TraditionalDatacenter Public

CloudHybrid Cloud

TraditionalDatacenter

Issues • Disparate Networks• Disjoint User Experience• Unpredictable SLAs• Different Locations

Transparency is a Key Requirement

Cloud Provider

TraditionalDatacenter

OpenCloud Bridge • Network transparency for Disparate Networks• Latency transparency to preserve the same User Experience• Services transparency to make SLAs predictable• Location transparency to allow Anywhere Access

Enabling Transparency Enables Hybrid Cloud

Hypervisor

LDAP DB Server

Private Public Public Private

Premise Datacenter Cloud

OpenCloud Bridge Use-Case

vSwitch

Hypervisor

vSwitch

Switch Switch

Storage

IP: 192.168.1.100Subnet: 255.255.254.0Reqs: DB, Web and LDAP

Network: 10.2.1.0Subnet: 255.255.254.0

= Netscaler VPX

It’s Your Budget … Spend it Wisely

•Vendor lock-in great for vendor

•Beware product lifecycles and tool set changes

Single Vendor

•ROI Calculators always show vendor author as best

•Use your own numbers

ROI Can be Manipulated

•Over buying is costly; get what you need

•Support call priority with tiered models

Understand Support Model

•Some projects have requirements best suited to specific tool

•Understand deployment and licensing impact

Use Correct Tool

•Blanket purchases benefit only vendor

•Chargeback to project for feature requirements

Leverage Costly Features as Required

• Social Media• Twitter: @XenServerArmy• Facebook: http://www.facebook.com/CitrixXenServer• LinkedIn: http://www.linkedin.com/groups?mostPopular=&gid=3231138

• Major Events• XenServer Master Class – March 23rd next edition• Citrix Synergy – San Francisco May 25-27 2011 (http://citrixsynergy.com)

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