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B99705021 資管三 李奕德 http://ppt.cc/41rH. improving the Scalability of Data Center Networks with Traffic-aware Virtual Machine Placement. Outline . Introduction Background Virtual machine placement Algorithm Algorithm evaluation Result Discussion and future work. introduction.
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B99705021 資管三 李奕德 http://ppt.cc/41rH improving the Scalability of Data Center Networks with Traffic-aware Virtual Machine Placement
Outline • Introduction • Background • Virtual machine placement • Algorithm • Algorithm evaluation • Result • Discussion and future work
introduction • Scalability issue • Aim to solve different problem - Dcell, Bcube, PortLand, VL2…… • No thinking of traffic issue - high traffic from end to end
introduction • three character of all traffic • average pairwise traffic rate & end-to-end cost has low correlation • Uneven between VMs • Stays almost the same • Traffic-aware placement may be beneficial
introduction • Traffic-aware VM Placement Problem (TVMPP) • given: traffic matrix , cost matrix • Goal: minimize cost • Cost can be: Total switch used/Compute Time • An algorithm that solve the NP-hard problem • Architecture difference
NP- hard • NP: by nondeterministic algorithms in polynomial time • nondeterministic -Every “guess by hunch” is right • at least as hard as the hardest problems in NP
Outline • Introduction • Background • Virtual machine placement • Algorithm • Algorithm evaluation • Result • Discussion and future work
Background – traffic analysis • Data set I : • IBM Global Services’ data warehouse • About 17000 virtual machines • Data set II: • Server cluster • About Hundreds of virtual machines • round-trip latency measurement at 68 VM
Background- traffic analysis • Uneven between VMs • 80% of VM’s traffic < 800kb/sec • 4% of VM’s traffic > 8mb/sec
Background- traffic analysis • Stays almost the same
Background- traffic analysis • Low correlation between average pairwise traffic rate & end-to-end cost • Correlation : -0.32
Background - Achitecture • Old style
Background - Achitecture • VL2
Background - Achitecture • Portland • Bcube
Outline • Introduction • Background • Virtual machine placement • Algorithm • Algorithm evaluation • Result • Discussion and future work
Virtual machine placement- cost function • n VM to assign • n slot for VM • static and single-path routing • Cost and traffic matrix from historical data
Virtual machine placement- cost function • is equivalent of finding • Dummy VM is assigned when no. slot > no. VM
Virtual machine placement- complexity • Quadratic Assignment Problem (NP-hard) • Impossible to find optimality when size > 15 • TVMPP is a special case of QAP • reduction from Balanced Minimum K-cut Problem (BMKP) • BMKP: extended problem from the Minimum Bisection Problem (MBP) • BMKP & MBP are NP-hard
Outline • Introduction • Background • Virtual machine placement • Algorithm • Algorithm evaluation • Result • Discussion and future work
Algorithm • approximation algorithm Cluster-and-Cut • Divide VM into VM cluster • Divide slot into slot cluster • Put VM cluster into slot cluster • A smaller problem • Feasible when size is sufficient small
Algorithm - complexity • Complexity determine by SlotClustering and VMMinKcut • Slotclustering: O(nk) • VMMinKcut: O(n4) • Total complexity = O(n4)
Outline • Introduction • Background • Virtual machine placement • Algorithm • Algorithm evaluation • Result • Discussion and future work
Algorithm evaluation- cluster and cut • Cluster and cut VS. other benchmark algorithms • Local Optimal Pairwise Interchange (LOPI) • Simulated Annealing (SA) • hybrid traffic model • Gravity model • compute the GLB for each settings
Outline • Introduction • Background • Virtual machine placement • Algorithm • Algorithm evaluation • Result • Discussion and future work
Result • Cost matrix • Compare with random assign
Result • Traffic is assumed to be in normal distribution • Variance is change to show difference • Different architecture & variance affect result
Result • View as VM cluster • GLB prediction
Result • GLB prediction VS. optimal solution
conclusion • Thing that brings better performance: - bigger variance - smaller cluster (less VM in a group) - Architecture difference (generally) Bcube > tree > fat-tree > VL2 • Good scenario: multiple service in a data center • Bad scenario: single service / map-reduce
Outline • Introduction • Background • Virtual machine placement • Algorithm • Algorithm evaluation • Result • Discussion and future work
Discussion and future • Dynamic VM placement • Other VM placement with different goal