Power Aware Virtual Machine Placement Yefu Wang

2 ECE Introduction Data centers are underutilized – Prepared for extreme workloads – Commonly under 20% utilized Shutting down unused servers – Saves more power than DVFS – Application correctness should be guaranteed Design choices – Workload redirection – VM live migration – Workload redirection + VM live migration [Meisner’09]

3 ECE Design Choice (1) : Workload Redirection Web requests Example: [Heo’07]

4 ECE Design Choice (2): VM Live Migration VM Example: [Wang’09, Verma’08]

5 ECE Design Choice (3): Hybrid [Kusic’08] 6 servers and 12 VMs 2 applications: Gold and Silver HTTP requests are dispatched by a dispatcher

pMapper: Power and Migration Cost Aware Application Placement in Virtualized Systems Akshat Verma, Puneet Ahuja, Anindya Neogi IBM India Research Lab, IIT Delhi

7 ECE Application Placement Static vs. dynamic placement – Utilization of each server shows dynamic pattens – Dynamic placement saves more energy – A later paper from the save authors advocates static placement System administrators have more control CPU utilization(0%-100%) are mapped to grayscale (0-1) in this figure.

8 ECE Application Placement Architecture VM resizing + idling DVFS

9 ECE Optimization Formulations Cost performance tradeoff Cost Minimization with Performance Constraint Performance benefit maximization with power constraint Performance benefitPowerMigration Cost

10 ECE System Modeling Migration Cost – Independent of the background workload – Can be estimated a priori Performance modeling – This paper does not design a performance controller – pMapper can be integrated with other performance controllers or models Power model – It is infeasible to have an accurate power model in practice Server power consumnption depends on the hosted applications The potential server-VM mappings can be huge – This paper only relies on the power efficiency of servers

11 ECE Optimization Formulations Cost performance tradeoff Cost Minimization with Performance Constraint Performance benefit maximization with power constraint Performance benefitPowerMigration Cost

12 ECE mPP Algorithm VM Server 1Server 2Server 3Server 4Server 5

13 ECE mPP Algorithm VM Server 1Server 2Server 3Server 4Server 5

14 ECE mPP Algorithm VM Server 1Server 2Server 3Server 4Server 5 Sort VMs by size

15 ECE mPP Algorithm VM Server 1Server 2Server 3Server 4Server 5 Sort servers by slope (power efficiency)

16 ECE mPP Algorithm VM Server 1Server 2Server 3Server 4Server 5 Allocate the VM to servers using First Fit

17 ECE mPP Algorithm VM Server 1Server 2Server 3Server 4Server 5 mPP algorithm is oblivious of the last configuration May entail large-scale migrations.

18 ECE mPPH Algorithm : mPP with History VM mPP

19 ECE mPPH Algorithm : mPP with History VM Target Util. Target Util. Target Util. Receiver Donor

20 ECE mPPH Algorithm : mPP with History VM Donor Target

21 ECE mPPH Algorithm : mPP with History VM Donor Pick the smallest VMs that add to a migration list Migration list Target

22 ECE mPPH Algorithm : mPP with History VM Receiver VM Migration list VM Donor

23 ECE mPPH Algorithm : mPP with History VM Receiver VM Migration list VM Donor Target

24 ECE mPPH Algorithm : mPP with History VM Receiver VM Migration list VM Donor Target

25 ECE mPPH Algorithm : mPP with History VM Receiver VM Donor Target mPPH algorithm tries to minimize migrations by migrating as few VMs as possible pMaP algorithm: before each migration, consider the benefit and migration cost

26 ECE System Implementation Testbed – Virtulization platform: VMware ESX 3.0 – Power monitor: IBM Active Energy Manager – Performance manager: EWLM – DVFS is not implemented Simulator – Replace performance manager with trace data – Simulating 4 blades, 42 VMs Baselines – Load balanced – Static

27 ECE Power Consumption mPP, mPPH saves 25% of power

28 ECE Algorithm Cost mPP fails at high utilization pMaP has the least overall cost most of the time

29 ECE Conclusion Application placement controller pMapper – Minimize power and migration cost – Meet performance guarantees Also avaiable in the paper: – More simulation results – Proof of the propoties of the algorithm for a given platform

Performance-Controlled Power Optimization for Virtualized Clusters with Multi-tier Applications Yefu Wang and Xiaorui Wang University of Tennessee, Knoxville

31 ECE Introduction Power saving techniques – DVFS have a small overhead – Server consolidation saves more power Performnce guarantee – Multi-tier applications may span multiple VMs – A controller must respond to a workload variation quickly Integrating performance control and server consolidation is important

32 ECE Application- level Response Time Controller Application- level Response Time Monitor Application- level Response Time Controller Application- level Response Time Monitor System Architecture VM Application- level Response Time Controller Application- level Response Time Monitor CPU Resource Demands Power Optimizer VM migration and server sleep/active commands

33 ECE Response Time Controller VM1VM2 Application HTTP requests Response Time Monitor MPC Controller Response Time Model CPU requirements

34 ECE CPU Resource Arbitrator CPU resource arbitrator – Runs at server level – Collect the CPU requirements of all VMs – Decides CPU allocations of all VMs and DVFS level of the server The CPU resource a VM receives depends on: – CPU allocation Example: give 20% CPU to VM1 – DVFS level Example: Set the CPU frequency to

35 ECE CPU Resource Arbitrator Two observations – Performance depends on – Keeping a constant, a lower leads to less power consumption CPU resource arbitrator – Use the lowest possible CPU frequency to meet the CPU requirements of the hosted VMS

36 ECE VM Consolidation for Power Optimization Problem formulation – Minimize the total power consumption of all servers – Meet all CPU resource requirements Power Model

37 ECE Optimization Algorithm 1.Minimum slack problem for a single server 2.Power aware consolidation for a list of servers 3.Incremental Power Aware Consolidation (IPAC) algorithm 4.Cost-aware VM migration

38 ECE Minimum slack problem for a single server VM Server Slack=1Minimum Slack=1

39 ECE Minimum slack problem for a single server VM Server VM Slack=0.8Minimum Slack=0.8

40 ECE Minimum slack problem for a single server VM Server VM Slack=0.2Minimum Slack=0.2

41 ECE Minimum slack problem for a single server VM Server VM Slack=0.2

42 ECE Minimum slack problem for a single server VM Server VM Slack=0.5Minimum Slack=0.2

43 ECE Minimum slack problem for a single server VM Server VM Slack=0.2Minimum Slack=0.2

44 ECE Minimum slack problem for a single server VM Server VM Slack=0 Algorithm stops if minimum slack < Sounds like exhaustive search? Complexity: the maximum number of VMs a server can host Fast in practice [Fleszar’02] Gives better solution than FFD Minimum Slack=0.2

45 ECE Consolidation Algorithm Power aware consolidation for a list of servers – Begin from the most power efficient server – Use minimum slack algorithm to fill the server with VMs – Repeate with the next server untill all the VMs are hosted Incremental Power Aware Consolidation (IPAC) algorithm – Everytime only consider these VMs for consolidation: Selected VMs on overloaded servers The VMs on the least power efficient server – Repeate until the number of servers does not decrease Cost-aware VM migration – Consider the benefit and migration cost before each migration Benefit: power reduction estimated by the power model, etc. Cost: administrator-defined based on their policies

46 ECE System Implementation Testbed – 4 servers, 16 VMs – 8 applications (RUBBoS) – Xen 3.2 with DVFS Simulator – Use CPU utilization trace file for 5415 servers to simulate 5415 VMs – 400 physical servers with random power models – 3 different type of CPUs

47 ECE Response Time Control Our solution Baseline: pMapper Violation of performance requirements Lower power consumption resulted from DVFS

48 ECE Server Consolidation 69.6% power is saved Response time is still guaranteed after the consolidation

49 ECE Simulation Results IPAC saves more power than pMapper – Algorithm gives better consolidation solutions – Even more power is saved by DVFS IPAC runs even faster than pMapper – Only a small number of VMs are considered in each period

50 ECE Conclusion Performance-controlled power optimization solution for virtualized server clusters – Application-level performance guaranteed – Power savings are provided by DVFS and server consolidation Compared with pMapper – Provides performance guarantee – Consumes less power – Less computational overhead

51 ECE Critiques to pMapper Too many components are only disscussed without implementation Lacks hardware experiments Only provides small scale simulations

52 ECE Critiques to IPAC Realword constraints are not shown in experiments – Network constraint, etc. Centralized solution – Incures a heavy conmunication overhead to the optimizer The settling time of the response time controller is too long

53 ECE Comparisons of the Two Papers pMapperIPAC Performance guaranteeNoYes DVFSNoYes Hardware experimentsNoYes Based algorithmsFFDMinimum Slack