View
219
Download
0
Tags:
Embed Size (px)
Citation preview
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
2
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
3
Outline• Virtual machine grid computing
• Virtuoso system
• Networking challenges in Virtuoso
• Enter VNET
• VNET, VTTIF Adaptive virtual network
• Experiments
• Current Status
• Conclusions
4
Aim
Grid Computing
New Paradigm
Traditional Paradigm
Deliver arbitrary amounts of computational power to perform distributed and parallel computations
Problem1:
Grid Computing using virtual machines
Problem2:
Solution
How to leverage them?
Virtual Machines What are they?
6b
6a
5
4
3b3a
2
1
Resource multiplexing using OS level mechanism
Complexity from resource user’s perspective
Complexity from resource owner’s perspective
Virtual Machine Grid Computing
5
Virtual Machines
Virtual machine monitors (VMMs)
•Raw machine is the abstraction
•VM represented by a single image
•VMware GSX Server
6
The Simplified Virtuoso Model
Orders a raw machine
User
Specific hardware and performance
Basic software installation available
User’s LAN
VM
Virtual networking ties the machine back to user’s home network
Virtuoso continuously monitors and adapts
7
User’s View in Virtuoso Model
User
User’s LAN
VM
8
Outline• Virtual machine grid computing
• Virtuoso system
• Networking challenges in Virtuoso
• Enter VNET
• VNET, VTTIF Adaptive virtual network
• Experiments
• Current Status
• Conclusions
9
User’s friendlyLAN
Foreign hostile LAN
Virtual Machine
Why VNET? A Scenario
IP network
User has just bought
10
User’s friendlyLAN
Foreign hostile LAN
Virtual Machine
VNET: A bridge with long wires
Host
Proxy
X
Why VNET? A Scenario VM traffic going out on foreign LAN
IP network
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?
11
User’s LAN
Foreign LAN 1
Host 2+
VNET
Proxy+
VNET
VNET startup topology
IP network
Host 3+
VNETHost 4
+VNET
Host 1+
VNET
Foreign LAN 3Foreign LAN 4
Foreign LAN 2
VM 1
VM 4VM 3
VM 2
TCP Connections
12
HostHost
vmnet0
Ethernet Packet Tunneledover TCP/SSL Connection
Ethernet Packet Captured by Interface in Promiscuous mode
“Host Only” Network
Ethernet Packet is Matched against the Forwarding Table on that VNET
Ethernet Packet is Matched against the Forwarding Table on that VNET
First link Second link (to proxy)
Local traffic matrix inferred by VTTIF
Periodically sent to the VNET on the Proxy
VNET
ethz
VM
“eth0”
VNET
ethy
IP Network
VM“eth0”
vmnet0
A VNET Link
13
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
14
VTTIF Operation
Synced Parallel Traffic Monitoring
Traffic Filtering and Matrix Generation
Matrix Analysis and Topology Characterization
15
Dynamic Topology Inference
1. Fast updates
Smoothed Traffic Matrix 2. Low Pass Filter
Aggregation
3. Threshold change detectionTopology change output
VNET Daemons VNET
Daemons
VTTIF parameters•Update rate•Smoothing interval•Detection threshold
16
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Rep
orte
d C
hang
e R
ate
(Hz)
Topology Change Rate (Hz)
Knee of Curve Depends
On VTTIF Threshold
and Smoothing Parameters
Reaction time of VTTIF
17
Outline• Virtual machine grid computing
• Virtuoso system
• Networking challenges in Virtuoso
• Enter VNET
• VNET, VTTIF Adaptive virtual network
• Experiments
• Current Status
• Conclusions
18
Adaptation
Virtuoso presents tremendous opportunities and challenges
Adapt to available resources
ChallengesNetwork and host monitoring
Monitor application
Infer goals of application
Adequacy of available mechanisms
Challenges interrelated
To determine subset of applications for which such adaptation succeeds
We demonstrate that the subset is not empty
19
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
20
Foreign hostLAN 1
User’sLAN
Host 2+
VNET
Proxy+
VNET
IP network
Host 3+
VNET
Host 4+
VNET
Host 1+
VNET
Foreign host LAN 3
Foreign host LAN 4
Foreign host LAN 2
VM 1
VM 4VM 3
VM 2
Resilient Star Backbone
Merged matrix as inferred by VTTIF
Illustration of dynamic adaptation in Virtuoso Fast-path links amongst
the VNETs hosting VMs
21
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
22
0
0.5
1
1.5
2
2.5
3
3.5
Sec
onds
0.94
1.6
3.23
2.92
2.268
Reaction Time
23
idea
lco
mpl
ete
star 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
0
200
400
600
800
1000
1200
1400
1600
1800
Run
Tim
e (S
econ
ds)
Number of Fast Path Links in Virtual Topology
No Fast Path Topology
Full all-to-all network afterstartup measurement+ reconfiguration cost
Full all-to-all frombeginning of run
Dynamic measurement andreconfiguration
Benefits of AdaptationBenefits 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
24
idea
l
com
ple
te
sta
r 1 2 3 4 5 6 70
100
200
300
400
500
600
700
800
900
Run
Tim
e (
Se
con
ds)
Number of Fast Path Links in Virtual Topology
No Fast Path Topology
Full bus network after startupmeasurement + reconfiguration cost
Full bus from beginning of run
Dynamic measurement andreconfiguration
•Patterns has a bus topology
•Eight VMs are used
•VMs spread over two clusters over a MAN
Benefits of AdaptationBenefits accrued as a function of the number of fast-path links added
25idea
lco
mpl
ete
star 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
0
200
400
600
800
1000
1200
1400
1600
1800
Run
Tim
e (S
eco
nds)
Number of Fast Path Links in Virtual Topology
No Fast Path Topology
Full all-to-all network after startupmeasurement + reconfiguration cost
Full all-to-all frombeginning of run
Dynamic measurement andreconfiguration •Patterns has an all-
all topology
•Eight VMs are used
• VMs are spread over WAN
Benefits of AdaptationBenefits accrued as a function of the number of fast-path links added
26
Outline• Virtual machine grid computing
• Virtuoso system
• Networking challenges in Virtuoso
• Enter VNET
• VNET, VTTIF Adaptive virtual network
• Experiments
• Current Status
• Conclusions
27
Current Status
• Applications: Transactional web ecommerce application
• Mechanisms: VM migration
28
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
29
• 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
30
Isn’t It Going to Be Too Slow?Application Resource ExecTime
(10^3 s)
Overhead
SpecHPC Seismic
(serial, medium)
Physical 16.4 N/A
VM, local 16.6 1.2%
VM, Grid virtual FS
16.8 2.0%
SpecHPC
Climate
(serial, medium)
Physical 9.31 N/A
VM, local 9.68 4.0%
VM, Grid virtual FS
9.70 4.2%
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 2.0NFS-based grid virtual file system between UFL (client) and NWU (server)
Small relativevirtualizationoverhead;compute-intensive
Relativeoverheads < 5%
31
Isn’t It Going To Be Too Slow?
0
0.5
1
1.5
2
2.5
3
0
0.5
1
1.5
2
2.5
3
No Load Light Load Heavy Load
Tasks onPhysicalMachine
Tasks onVirtual
Machine
Tasks onPhysicalMachine
Tasks onVirtual
Machine
Tasks onPhysicalMachine
Tasks onVirtual
Machine
Synthetic benchmark: exponentially arrivals of compute bound tasks, background load provided by playback of traces from PSC
Relative overheads < 10%
32
Isn’t 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 Workstation’s 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