Reliability Support in Virtual Infrastructures

Transcription

1 Reliability Support in Virtual Infrastructures 2 nd IEEE International Conference on Cloud Computing Technology and Science, Indianapolis, 2010 RESO Guilherme Koslovski (INRIA University of Lyon) Wai-Leong Yeow (DoCoMo USA Labs) Cedric Westphal (DoCoMo USA Labs) Tram Truong Huu (University of Nice I3S) Johan Montagnat (CNRS I3S) Pascale Vicat-Blanc Primet (INRIA - LYaTiss)

2 Reliability as a Service Reliability: probability that a system will survive failures Availability: fraction of time that a system is functional 99.95% availability 99.9% availability 99.95% reliability Actually nothing more than SLAs. Failure => credits Lock-ins No guarantees at all 100% uptime 100% network uptime 2

3 Context Convergence of computing and communication: Virtual Infrastructure is a concept emerging from Virtual Networks and Infrastructures as a Service New models and tools to manage virtualized substrate & to help users in execution of their applications Users Distributed & virtualized substrate Network virtualization Resources virtualization Grid computing experience Complex applications IaaS, PaaS, XaaS concepts 3

4 Issue Network and IT resources are subject to random failures Failures can be measured: mean time between failures (MTBF) Impact of a failure on a distributed application: worker node failure: can affect the total execution time database and servers: can compromise the entire execution Some applications can recover from failures but This process usually affects the execution time This complicates the application development 4

5 Our proposal Reliability as a service offered by the infrastructure provider Provide me a basic infrastructure Provide me a reliable infrastructure User VM 1 PM Application VM 2 PM BKP 1 PM BKP 2 PM VM n PM BKP n PM 5

6 Our proposal Reliability becomes a service offered by the infrastructure provider Transparent realibility provisioning Users (applications) have no knowledge about physical failures User VM 1 PM Application VM 2 PM BKP 1 PM BKP 2 PM VM n PM BKP n PM 6

7 Outline Providing Transparent Reliability Reliable Virtual Infrastructure description Automatic generation of backup nodes and backup links Allocation algorithm Evaluation through a use case application Conclusion & Future work 7

8 Mechanism for providing transparent reliability I. Virtual Infrastructure description II. Translation of reliability requirements into real backup nodes III. Allocation of a reliable virtual infrastructure 8

9 Virtual Infrastructure description: VXDL language VXDL file General description VXDL: Virtual private execution infrastructure Description Language vm1 Resources description Network topology description Timeline description database [1 GB, 2 GB] 2 GHz 2 cores Location: lyon.fr Reliability: 99.99% workers [100 nodes] 1 GB, 2 GHz 2 cores Location: lyon.fr Reliability: 99.9% 9

10 Virtual Infrastructure extension Translation of reliability requirements into replica nodes Opportunistic Redundancy Pooling (ORP) mechanism [W. Yeow et al, 2010]: Input: Reliability level (user requirement) Probability of physical failures (from MTBF) Number of protected virtual nodes (user requirement) Output: the number of backup nodes Backup nodes can be shared among different groups of critical nodes For example, two sets of backup nodes (k1 and k2) can be shared to protect two groups of critical nodes. Thanks to ORP is required only the min(k1, k2) [W. Yeow et al, 2010]: Designing and embedding reliable virtual infrastructures, VISA workshop

11 Virtual Infrastructure extension Backup links: consistent network topology Step 1 Step 3 Step 2 11

12 Allocation of a Reliable Virtual Infrastructure An extended graph is composed by original description + backup components Backup components can have specific constraints: For example, original node and backup node should be allocated on different physical racks Subgraph-isomorphism detection [Lischka et al, 2009] Physical substrate Embedded graph 12

13 From mapping to allocation The map provided by the allocation is interpreted and instantiate using the HIPerNet framework [P. Primet et al, 2010] Original VMs and replicas are synchronized by a modified version of the Remus live protection mechanism [B. Cully et al, 2008] 13

14 Evaluation through a use case application Bronze Standard: distributed large-scale application Quantifies the maximal error resulting from medical-image analysis Large databases: more the data, more the accuracy 31 VMs: 512 MB,1 GHz 10 Mbps for each virtual link between the database and the workers Two scenarios of reliability requirements: Database protection: a failure stops the application execution Workers protection: a failure increases the execution time Testbed: Grid 5000 Physical substrate is composed by 100 nodes: MTBF simulation values: 60000s, 30000s, 15000s [D. Atwood et al., 2008] I) Translated into VXDL II) Submitted to HIPerNet 14

15 Experimental results Goal: quantify the cost of a reliable virtual infrastructure Prices are based on Amazon EC2 for Europe We do not include any specific link pricing cost without reliability support (short term lease): $2.95 / h VM specifications Basic node Short term lease $0.095 Long term lease $0.031 Prices for computing nodes protection (30 VMs, 99.9%): MTBF s s s Backup Nodes Total cost Short term Reliability cost / total cost Total cost Long term Reliability cost / total cost 5 $ % $ % 8 $ % $ % 12 $ % $ % 15

16 Experimental results Goal: evaluate the application behavior when executing with reliability support Application makespan without substrate failures: 1205s, used as baseline Database protection: DB label: database is the unique component protected Makespan increases proportionally to the number of failures Worker nodes protection: WN label: only computing nodes are protected Makespan slightly increases MTBF NI DB Increase WN Increase 60000s 16.26% 0.2% 30000s 26.47% 1.7% DB WN 15000s 40.08% 3.2% 0 NI 60000s 30000s 15000s 16

17 Experimental results Goal: reliability service vs resubmission mechanism: Application is aware about substrate failures A task is resubmitted on a new computing node The makespan difference would have been more if backup nodes were not pre-allocated and configured 1600 MTBF Makespan Increase 60000s % 30000s % 15000s % Reliability Resubmission s 30000s 15000s 17

18 Conclusions Reliability becomes a service offered by the infrastructure provider We have developed a framework to provide transparent reliability: A language to specify the reliability requirements; A mechanism to interpret these requirements and transform it in replicas (nodes and links) A map and allocation process to provisioning the reliability level required by the user The framework was implemented on top of the HIPerNet framework, and validated over the Grid 5000 testbed Future work includes: the implementation of a mechanism to protect virtual links a detailed investigation on the economical aspects Tomorrow there is a demonstration about the industry version of the HIPerNet framework (LYaTiss core)

19 Thank you for your attention! Any questions? 19

20 Some references Specifying and provisioning Virtual Infrastructures with HIPerNET. Fabienne Anhalt, Guilherme Koslovski, and Pascale Vicat-Blanc Primet. ACM International Journal of Network Management (IJNM) - special issue on Network Virtualization and its Management, 2010; Joint elastic cloud and network framework for application performance optimization and cost reduction. Tram Truong Huu, Guilherme Koslovski, Fabienne Anhalt, Pascale Vicat-Blanc Primet, and Johan Montagnat. Journal of Grid Computing (JoGC), 2010; Reliability support in virtual infrastructures. Guilherme Koslovski, Wai-Leong, Cedric Westphal, Tram Truong Huu, Pascale Vicat-Blanc Primet, and Johan Montagnat. In 2 nd IEEE CloudCom 2010, Indianapolis, USA; A scalable security model for enabling Dynamic Virtual Private Execution Infrastructures on the Internet. Pascale Vicat-Blanc Primet, Jean-Patrick Gelas, Olivier Mornard, Guilherme Koslovski, Vincent Roca, Lionel Giraud, Johan Montagnat, and Tram Truong Huu. In IEEE/ACM CCGrid2009, Shanghai, May 2009; Exploring the virtual infrastructure service concept in Grid'5000. Pascale Vicat-Blanc Primet, Fabienne Anhalt, and Guilherme Koslovski. In 20th ITC Specialist Seminar on Network Virtualization, Hoi An, Vietnam, May 2009; Executing distributed applications on virtualized infrastructures specified with the VXDL language and managed by the HIPerNET framework. Guilherme Koslovski, Tram Truong Huu, Johan Montagnat, and Pascale Vicat-Blanc Primet. In CLOUDCOMP 2009, Munich, Germany, October 2009; Virtual Resources and Interconnection Networks Description Language. Guilherme Koslovski, Pascale Vicat-Blanc Primet, and Andrea Schwertner Charão. In GridNets 2008, Oct. 2008; HIPernet: A Decentralized Security Infrastructure for Large Scale Grid Environments. Julien Laganier, Pascale Vicat-Blanc Primet. In 6th IEEE/ACM International Conference on Grid Computing (GRID 2005), November 13-14, 2005, Seattle, Washington, USA, Proceedings, pages , IEEE; 20

21 Backup slides 21

22 ViPXi description: General description VXDL file General description VI identification (name, owner, users) Reservation (start and end time) Resources description Network topology description General properties: Location Security Monitoring Timeline description 22

23 ViPXi description: Resources VXDL file General description Resources description Network topology description Timeline description Resources and groups of resources Resources types: Virtual routers/switches Virtual machines Virtual storages Virtual access points Cross-layers parameters: Exclusivity Specific devices Location 23

24 ViPXi description: Network topology VXDL file General description Resources description Network topology description Topology description: - (Provisioned) virtual links Specification of QoS constraints: Bandwidth (forward and reverse) Latency Reliability Security Timeline description 24

25 ViPXi description: Timeline VXDL file General description Resources description - often components are not used simultaneously or all along the VI lifetime - an internal timeline for each VI can help optimizing the allocation, scheduling, and provisioning processes - a timeline is composed by stages, delimited by temporal marks Network topology description Timeline description 25

26 Reliability prices Total cost is: original cost + reliability cost Original cost Reliability cost 26

27 Evaluation through a use case application Bronze Standard workflow is analyzed and translated into a VXDL file: 31 VMs: 512 MB,1 GHz 10 Mbps for each virtual link between the database and the workers Two scenarios of reliability requirements: Database protection: a failure stops the application execution Workers protection: a failure increases the execution time Physical substrate: Grid 5000 testbed I) Translated into VXDL II) Submitted to HIPerNet 27

28 ViPXi description: reliability Reliability is informed by the user considering the information exposed by the physical substrate; vm1 Links l2, l3 [10 Mb/s, 100 Mb/s] Link - l1 [20 Mb/s, 200 Mb/s] with monitoring Routers r1, r2 Layer: Ethernet Node - vm2 Dynamically configured [1 GB, 2 GB] 2 GHz 2 cores Location: lyon.fr Reliability: 99.9% vm3 Link l4, l5 {10 Mb/s, 50 Mb/s, 100 Mb/s} Reliability: 99.99% vm4 28

29 Scenario composition and metrics Goals: Evaluate the application behavior when executing with reliability support Quantify the cost of a reliable ViPXi Application makespan without substrate failures: 1205s, used as baseline Simple cost model for the pricing: ViPXi cost + replicas cost Prices are based on Amazon EC2 for Europe 1 hour reservation We do not include any specific link pricing VM specifications Basic node (1.7GB RAM) Short term lease $0.095 Long term lease $0.031 ViPXi cost without reliability support (short term lease): $2.95, used as baseline Physical substrate is composed by 100 nodes: MTBF simulation values: 60000s, 30000s, 15000s 29

30 Experimental results Goal: Quantify the cost of a reliable ViPXi Prices are based on Amazon EC2 for Europe We do not include any specific link pricing cost without reliability support (short term lease): $2.95 Prices for database protection (1 VM, 99.99%): VM specifications Basic node Short term lease $0.095 Long term lease $0.031 MTBF s s s MTBF s s Fail prob. G. Koslovski, W. Yeow, C. Westphal, s Backup Nodes Total cost Short term Reliability cost / total cost Total cost Long term Reliability cost / total cost $3.13 6% $3.01 2% $ % $3.04 3% Prices for computing nodes protection (30 VMs, 99.9%): $ % $3.07 4% Short term Long term Fail prob. Backup Nodes Total cost Reliability cost / total cost Total cost Reliability cost / total cost $ % $ % $ % $ % $ % $ % 30