Post on 18-Dec-2015
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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: 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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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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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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Network Basic Functionalities/Features
Packet forwarding schemes
Bandwidth guarantees
Relative bandwidth sharing
Multipathing techniques
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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
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
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
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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Project
Feature
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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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.