VirtualizationAbdullah Aldhamin

June 3, 2013

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Outline Virtualization: what and why?

Server Virtualization Offerings

Shortcoming and Challenges on SV

Sustaining Performance while Virtualizing

Future Perspective on SV

Data Center Network Virtualization, what and why?

Overview of VN Projects and how they compare with each others

Future Perspective on DC Network Virtualization

Conclusions

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Virtualization Virtualization

Techniques, methods, approaches to create a virtual instance of a computing resource.

Why? Advances in h/w technologies, e.g. multi-core

H/W optimization Cloud computing Economic factors

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Server Virtualization Key features:

Multiple Isolated

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Server Virtualization: Offerings Improved H/W utilization

Consolidation VMs are just files

Faster provisioning and deployment Better availability and BC solutions

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Server Virtualization: Offerings Lower TCO

Longer h/w purchase cycle Smaller datacenter Lower maintenance, power, cooling … etc

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Server Virtualization: Challenges Performance:

CPU and Network Overhead to do virtual-related emulations A single NIC = shared bandwidth Not good for I/O bound apps Propagation delay latency

Storage Latency Needs enough physical storage power to support the

multiple VMs Memory

Amount needed for the application

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Server Virtualization: Challenges Scalability

How many VMs can each physical server accommodate?

Asset management Tracking a dynamic environment Service management burdens

Security Malicious access to the hypervisor means you’re

screwed up! Single-point of failure?

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Server Virtualization and Performance:Can we have both?

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Virtualization and Performance Selective virtualization Direct assignment of physical NICs to VMs

Isolation and and better I/O− Cost for more NICs and cabling− Flexibility constraints

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Virtualization and Performance Firmware-based I/O virtualization

Virtual I/O channels connected to the same NIC No true isolation, a channel will impact all other

channels H/W-based I/O virtualization

I/O channels are built in the H/W- Vendor-specific NICs

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Virtualization and Performance Consolidation in a shared resource pool

Allocate VMs to a resource pool instead of physical server

Dynamic resource allocation to VMs based on workload

Complexity and poor visibility on how performance is managed

Adds challenges to asset management

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Virtualization and Performance Management tools

Help manage performance, track SLAs and set priorities

Optimize resource allocation Proactive failure assessment

Advances in processors and memory Multiple logical CPUs and improved instructions

faster comm. between hypervisor and VMs Integrate I/O memory mgmt and DMA remapping

better I/O virtualization

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Highlights on SV Trends Open-source tools Joint collaboration between server virtualization

vendors and processors’ manufacturers Hardware-based hypervisor Convergence of server, storage, desktop and

apps virtualization.

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So… Server virtualization Pros and Cons How can we overcome (or minimize) the impact

on performance Future perspectives

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Is this enough? Does it solve everything we want

from Virtualization?

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Server Virtualization is NOT enough! No performance isolations Security Poor application deployability Limited management flexibility No support network innovation

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Data Center Network Virtualization Multiple virtual networks (VNs) on top of physical

network. Challenges

Addressing schemes Scalability Failure tolerance Security Resource management

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Examples of DC Network Topologies Conventional DC network topology

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Examples of DC Network Topologies Clos topology

Path diversity

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Examples of DC Network Topologies Fat-tree topology

K=4

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Network Basic Functionalities/Features Packet forwarding schemes Bandwidth guarantees Relative bandwidth sharing Multipathing techniques

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Examples of Virtual NetworkProposals/Implementations

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Traditional Data Center Objective: isolation between tenants Pros:

Uses VLANs to provide means of isolations Uses commodity switches and popular hypervisors SPs can have their own L2 & L3 address spaces

Cons: Imposes scalability concerns

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Diverter Objective: to provide software-based VN solution

for packet forwarding L3 network virtualization to allow tenants control

their addresses Software module VNET on every physical machine

Replaces VM MAC with physical MAC Special IP scheme (10.tenant.subnet.vm)

Lacking QoS

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NetLord Objective: virtual network designed to provide

solution for scalability of tenants, in order to increase resource utilization and revenue

Utilizes L2 and L3 virtualization: L2+L3 encapsulation Full address-space virtualization

Uses Diverter forwarding Uses SPAIN multipathing

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NetLord

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NetLord Pros:

Takes advantage of already implemented schemes to provide basic functionalities

Cons Not all commercial off-the-shelf switches support IP

forwarding Large packet encapsulation results in more drops

and fragmentation No bandwidth guarantee

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Oktopus Issues with multi-tenant data center networks:

Difficult application performance management Unpredictable network performance decrease app.

performance unhappy customers revenue lo$$e$ Objectives: to design virtual network abstractions and

to explore the trade-off between the guarantees offered to tenants, the tenant cost and provider revenue

Key design concept: two virtual network abstractions: Virtual cluster Virtual oversubscribed cluster

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Oktopus Cluster

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Oktopus Virtual cluster

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Oktopus Virtual oversubscribed cluster

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Oktopus Pros:

Increases application performance Flexibility to InP Balance between higher application performance

and lower cost Cons

Deployability: only for tree-like physical network topologies

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Gatekeeper Objectives: a virtual network to provide bandwidth

guarantees, and achieves high bandwidth utilization Design features:

Scalable in terms of number of VMs Predictable in terms of network performance Flexible based on minimum and maximum bandwidth

guarantees Design elements:

Minimum guaranteed rate Maximum allowed rate for each VM

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Gatekeeper

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Gatekeeper Pros:

Flexible bandwidth guarantees Cons:

Other performance features are not addressed Still under development Scale of experimental evaluation is small

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Seawall Objective: a virtual network to provide bandwidth

sharing in a multi-tenant data center network

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Seawall Pros:

Policy enforcement so no one tenant can consume all bandwidth

Dynamic nature allows for tenant requirement change adjustment

Cons: Deployability: currently for Windows and Hyper-V

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ProjectFeature

Forwarding Scheme

Bandwidth Guarantee

Multipathing Relative BW Sharing

Traditional DC ✔ ✔

Diverter ✔NetLord ✔ ✔VICTOR ✔

VL2 ✔ ✔PortLand ✔ ✔

SEC2 ✔ ✔SPAIN ✔

Oktopus ✔SecondNet ✔ ✔Gatekeeper ✔CloudNaaS ✔ ✔

Seawall ✔NetShare ✔ ✔

Classification of Projects by Feature

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Highlights on Research Direction Virtualized Edge Data Center: concerned about placement of

small data centers at the edge of the network to be closer to end-users

Benefits: Better QoS for delay sensitive applications Reduces network communication cost by reducing network traffic

across network providers Lower construction cost compared to large remote data centers

Challenges: Service placement problem: finding optimal trade-off between

performance and construction cost How to efficiently manage services hosted in multiple data centers?

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Highlights on Research Direction Virtual data center embedding algorithms: to

accommodate a high number of VDCs in data centers Dependent on how efficient virtual resources are

mapped to physical ones Challenges:

Need to consider all physical resources, in addition to servers

Dynamic nature of the demand for data center applications

Energy efficiency: how to optimize the placement of VMs and VNs for energy efficiency?

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Highlights on Research Direction Network performance guarantees:

The design and implementation for bandwidth allocation schemes

Find a good trade-off between maximizing network utilization and guaranteed network performance

Data center management: Monitoring Energy management Failure detection and handling

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Highlights on Research Direction Security:

Mitigating security vulnerabilities Monitoring and auditing infrastructure Support for multi-layer security depending on

tenants needs

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Conclusions Server virtualization: what and why? Techniques to address performance issues related

to server virtualization Datacenter network virtualization: what and why? Recent virtual network architectures: no ideal

project to solve all problems!

Future perspectives on server and network virtualization research: we still have a lot to do…

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Thank You!

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References Fauzi Kamoun, “Virtualizing the Datacenter Without Compromising Server

Performance”, ACM Ubiquity, Vol 2009, Issue 9. Md. Faizul Mari, et. al., “Data Center Network Virtualization: A Survey”, in IEEE

Communications Surveys & Tutorials, Vol 15, pg. 909-928, Sep 2012. [online] http://en.wikipedia.org/virtualization “Virtualization”, May 2013. T. Benson, et. al., “CloudNaaS: A Cloud Networking Platform for Enterprise

Applications”, SOCC’11, 2011. A. Edwards, et.al., “Diverter: A New Approach to Networking Within Virtualized

Infrastructures”, WREN’09, 2009. J. Mudigonda, et. al., “SPAIN:COTS Data-Center Ethernet for Multipathing over Arbitrary

Topologies,” in Proceedings ACM USENIX NSDI, April 2010.  J. Mudigonda, et. al., “NetLord: A Scalable Multi-Tenant Network Architecture for

Virtualized Datacen- ters,” in Proceedings ACM SIGCOMM, August 2011. F. Hao, et. al., “Enhancing Dynamic Cloud-based Services using Network Virtualization,”

in Proceedings ACM VISA, August 2009.