Dynamic Topology Adaptation of Virtual Networks of Virtual Machines

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Dynamic Topology Adaptation of Virtual Networks
of Virtual Machines

• Ananth I. Sundararaj
• Ashish Gupta
• Peter A. Dinda
• Prescience Lab
• Department of Computer Science
• Northwestern University
• http//virtuoso.cs.northwestern.edu

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Summary

• Dynamically adapt applications in virtual
  environments to available resources
• Demonstrate the feasibility of adaptation at the
  level of collection of VMs connected by VNET
• Show that its benefits can be significant for the
  case of BSP applications
• Studying the extent of applications for which our
  approach is effective

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Outline

• Virtual machine grid computing
• Virtuoso system
• Networking challenges in Virtuoso
• Enter VNET
• VNET, VTTIF Adaptive virtual network
• Experiments
• Current Status
• Conclusions

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Virtual Machine Grid Computing
Deliver arbitrary amounts of computational power
to perform distributed and parallel computations
Aim
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New Paradigm
Traditional Paradigm
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2
Grid Computing using virtual machines
Resource multiplexing using OS level mechanism
Grid Computing
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3a
6a
3b
Problem1
6b
Virtual Machines What are they?
Complexity from resource users perspective
Solution
Problem2
How to leverage them?
Complexity from resource owners perspective
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Virtual Machines
Virtual machine monitors (VMMs)

• Raw machine is the abstraction
• VM represented by a single
• image
• VMware GSX Server

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The Simplified Virtuoso Model
Virtual networking ties the machine back to
users home network
Users LAN
Specific hardware and performance
VM
Basic software installation available
Orders a raw machine
Virtuoso continuously monitors and adapts
User
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Users View in Virtuoso Model
Users LAN
VM
User
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Outline

• Virtual machine grid computing
• Virtuoso system
• Networking challenges in Virtuoso
• Enter VNET
• VNET, VTTIF Adaptive virtual network
• Experiments
• Current Status
• Conclusions

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Why VNET? A Scenario
Foreign hostile LAN
Users friendly LAN
IP network
User has just bought
Virtual Machine
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Why VNET? A Scenario
VM traffic going out on foreign LAN
Foreign hostile LAN
X
Users friendly LAN
IP network
Virtual Machine
Host

• A machine is suddenly plugged into a foreign
  network. What happens?
• Does it get an IP address?
• Is it a routeable address?
• Does firewall let its traffic
• through? To any port?

Proxy
VNET A bridge with long wires
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VNET startup topology
Foreign LAN 1
TCP Connections
Users LAN
VM 1
Host 1 VNET
IP network
Proxy VNET
Foreign LAN 2
Host 3 VNET
VM 2
VM 4
Host 2 VNET
Host 4 VNET
VM 3
Foreign LAN 3
Foreign LAN 4
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A VNET Link
Ethernet Packet Captured by Interface in
Promiscuous mode
First link
Second link (to proxy)
Host Only Network
VM
eth0
ethz
ethy
vmnet0
vmnet0
IP Network
VNET
VNET
Ethernet Packet Tunneled over TCP/SSL Connection
Host
Host
Ethernet Packet is Matched against the Forwarding
Table on that VNET
Ethernet Packet is Matched against the Forwarding
Table on that VNET
Local traffic matrix inferred by VTTIF
Periodically sent to the VNET on the Proxy
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VTTIF

• Topology inference and traffic characterization
  for applications
• Ethernet-level traffic monitoring
• VNET daemons collectively aggregate a global
  traffic matrix for all VMs
• Application topology is recovered using
  normalization and pruning algorithms

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VTTIF Operation
Synced Parallel Traffic Monitoring
Traffic Filtering and Matrix Generation
Matrix Analysis and Topology Characterization
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Dynamic Topology Inference

• VTTIF parameters
• Update rate
• Smoothing interval
• Detection threshold

VNET Daemons
VNET Daemons
1. Fast updates
Smoothed Traffic Matrix
2. Low Pass Filter Aggregation
3. Threshold change detection
Topology change output
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Reaction time of VTTIF
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Outline

• Virtual machine grid computing
• Virtuoso system
• Networking challenges in Virtuoso
• Enter VNET
• VNET, VTTIF Adaptive virtual network
• Experiments
• Current Status
• Conclusions

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Adaptation
Adapt to available resources
Virtuoso presents tremendous opportunities and
challenges
Challenges
Network and host monitoring
Adequacy of available mechanisms
Monitor application
Infer goals of application
Challenges interrelated
To determine subset of applications for which
such adaptation succeeds
We demonstrate that the subset is not empty
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Experiments

• Focus on a specific instance
• Application Patterns, a synthetic benchmark
• Monitoring Application topology inferred by
  VTTIF
• Aim Minimize running time of patterns
• Mechanism Add links and corresponding
  
• forwarding rules to VNET topology

Performance of BSP applications significantly
enhanced by adapting VNET topology, guided by
topology inferred by VTTIF
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Illustration of dynamic adaptation in Virtuoso
Fast-path links amongst the VNETs hosting VMs
Resilient Star Backbone
Foreign host LAN 1
Users LAN
VM 1
Host 1 VNET
IP network
Proxy VNET
Merged matrix as inferred by VTTIF
Foreign host LAN 2
VM 2
VM 4
VM 3
Host 3 VNET
Host 2 VNET
Host 4 VNET
Foreign host LAN 4
Foreign host LAN 3
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Evaluation

• Reaction time of VNET
• Benefits of adaptation (performance speedup)
• Eight VMs on a single cluster, all-all topology
• Eight VMs spread over two clusters over MAN, bus
  topology
• Eight VMs spread over WAN, all-all topology

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Reaction Time
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Benefits of Adaptation
Benefits accrued as a function of the number of
fast-path links added

• Patterns has an all-all topology
• Eight VMs are used
• All VMs are hosted on the same cluster

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Benefits of Adaptation
Benefits accrued as a function of the number of
fast-path links added

• Patterns has a bus topology
• Eight VMs are used
• VMs spread over two clusters over a MAN

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Benefits of Adaptation
Benefits accrued as a function of the number of
fast-path links added

• Patterns has an all-all topology
• Eight VMs are used
• VMs are spread over WAN

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Outline

• Virtual machine grid computing
• Virtuoso system
• Networking challenges in Virtuoso
• Enter VNET
• VNET, VTTIF Adaptive virtual network
• Experiments
• Current Status
• Conclusions

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Current Status

• Applications Transactional web ecommerce
  application
• Mechanisms VM migration

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Conclusions

• Demonstrated the feasibility of adaptation at the
  level of collection of VMs connected by VNET
• Showed that its benefits can be significant for
  the case of BSP applications
• Studying the extent of applications for which our
  approach is effective
• Moving ahead to use other adaptation mechanisms

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• For More Information
• Prescience Lab (Northwestern University)
• http//plab.cs.northwestern.edu
• Virtuoso Resource Management and Prediction for
  Distributed Computing using Virtual Machines
• http//virtuoso.cs.northwestern.edu
• VNET is publicly available from
• http//virtuoso.cs.northwestern.edu

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Isnt It Going to Be Too Slow?
Small relative virtualization overhead compute-in
tensive
Relative overheads lt 5
Experimental setup physical dual Pentium III
933MHz, 512MB memory, RedHat 7.1, 30GB disk
virtual Vmware Workstation 3.0a, 128MB memory,
2GB virtual disk, RedHat 2.0 NFS-based grid
virtual file system between UFL (client) and NWU
(server)
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Isnt It Going To Be Too Slow?
Synthetic benchmark exponentially arrivals of
compute bound tasks, background load provided by
playback of traces from PSC Relative overheads lt
10
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Isnt It Going To Be Too Slow?

• Virtualized NICs have very similar bandwidth,
  slightly higher latencies
• J. Sugerman, G. Venkitachalam, B-H Lim,
  Virtualizing I/O Devices on VMware Workstations
  Hosted Virtual Machine Monitor, USENIX 2001
• Disk-intensive workloads (kernel build, web
  service) 30 slowdown
• S. King, G. Dunlap, P. Chen, OS support for
  Virtual Machines, USENIX 2003
• However May not scale with faster NIC or disk