1. On the Use of Service Level Agreements in AssessGrid

2. Dominic Battré - On the Use of SLAs in AssessGrid 2 Overview Motivation AssessGrid Negotiation Scenarios End-user Layer Broker Layer Grid Fabric Layer

3. Dominic Battré - On the Use of SLAs in AssessGrid 3 Motivation AssessGrid AssessGrid Aim - integrate a risk-aware Service Level Agreement model into current Grid technology Risk awareness incorporated across three layers

4. Dominic Battré - On the Use of SLAs in AssessGrid 4 What is risk? Risk: Combination of the probability of an event and its consequences

5. Dominic Battré - On the Use of SLAs in AssessGrid 5 What is risk? Risk as a negative force … - Avoid it using risk management Risk as a positive force … - Opportunities may be created as a result of risk taking - Potential benefits when taking certain risk Risk management - Identification and treatment of risk

6. Dominic Battré - On the Use of SLAs in AssessGrid 6 Why risk management? low risk middle risk high risk Grid Resource Provider - estimates the risk for agreeing an SLA - considers risk of resource failure for scheduling - initiates precautionary fault-tolerance mechanisms

7. Dominic Battré - On the Use of SLAs in AssessGrid 7 Why risk management? Grid Resource Broker - Published PoF enables to compare different offers Risk, QoS, charge, and penalty fee - Reliability measure will classify trustful providers - Estimates risks for building workflows PoF

8. Dominic Battré - On the Use of SLAs in AssessGrid 8 Why risk management? End User?!? is happy… - Knows its risks. - Can pick most suitable provider!

9. Dominic Battré - On the Use of SLAs in AssessGrid 9 Scenario 1: User – Provider Neg. Get Template Fill Template - Job description - Max. PoF - Min. Penalty Create Offer - Set Price SLA Request SLA Offer CommitContract

10. Dominic Battré - On the Use of SLAs in AssessGrid 10 Scenario 2a: Broker = Mediator Template Subscription Get Templates

11. Dominic Battré - On the Use of SLAs in AssessGrid 11 Scenario 2a: Broker = Mediator SLA Request SLA Offer Evaluate Reliability Medium PoF Low PoF 1000 EUR, 1%1000 EUR, 1.5%

12. Dominic Battré - On the Use of SLAs in AssessGrid 12 Scenario 2a: Broker = Mediator Commit Timeout

13. Dominic Battré - On the Use of SLAs in AssessGrid 13 Scenario 2b: Broker = Contractor

14. Dominic Battré - On the Use of SLAs in AssessGrid 14 Architectural Overview End-user - Portal Broker - Risk Assessor - Confidence Service - Workflow Assessor Provider - Negotiator - Scheduler - Risk Assessor - Consultant Service

15. Dominic Battré - On the Use of SLAs in AssessGrid 15 End-User Layer – Portal Architecture Presentation - of SLA templates, requests, offers - of PoF and reliability information - of status of executing and pending jobs - SLA violations and compensation (penalties) - specific to user role (end user, administrator) Follows the MVC (Model View Controller) design pattern Based on GridSphere portal architecture

16. Dominic Battré - On the Use of SLAs in AssessGrid 16 Broker Layer Inspired by GridWay scheduler SLA Processor: Agreement and AgreementFactory WebService Resource Filter: find suitable resources that are likely to respond Offer Manager: Used if broker acts as provider Scenario 2b

17. Dominic Battré - On the Use of SLAs in AssessGrid 17 Grid Fabric Layer NegotiationManager -Agr./Agr.Fact. WS -checks whether offer complies to template -initiation of file transfers Scheduler -creates tentative schedules for offers Risk Assessor Consultant Service -records data -builds models

18. Dominic Battré - On the Use of SLAs in AssessGrid 18 Summary Motivation AssessGrid Negotiation Scenarios End-user Layer Broker Layer Grid Fabric Layer Questions

19. Dominic Battré - On the Use of SLAs in AssessGrid 19 Questions? I will not ask questions about the math involved. I will not ask questions about the math involved. I will not ask questions about the math involved. I will not ask questions about the math involved.

20. Dominic Battré - On the Use of SLAs in AssessGrid 20 Implications of Scenarios Provider needs to modify SLA request - Price complex function of PoF and penalty - Therefore, user cannot be committed Broker needs to collect offers, but - User must not be committed to request - createAgreement returns only one offer - Offers need expiration time (determined by user) - Templates should be similar/identical to offer choice by broker - Templates may not depend on user Broker negotiates on behalf of somebody else - needs to be communicated

21. Dominic Battré - On the Use of SLAs in AssessGrid 21 Fabric Layer – Extending CCS

22. Dominic Battré - On the Use of SLAs in AssessGrid 22 Implementation with Globus Toolkit 4 Why Globus? - Utility: Authentication, Authorization, Delegation, RFT, MDS, WS-Notification - Impact Problem 1: GRAM (Grid Resource Allocation and Management) - State machine, incl. File-Staging, Delegation of Credentials, RSL - Cannot use it: written for batch schedulers, nor for planning schedulers Problem 2: Deviations from WS-AG spec. - Different Namespaces WS-A, WS-RF

23. Dominic Battré - On the Use of SLAs in AssessGrid 23 Implementation with Globus Toolkit 4 Technical Challenges - xs:anyType Wrote custom serializers/deserializers - Subtitution groups Used in ItemConstraint (Creation Constraints) Cannot be mapped to Java by Axis Replaced by xs:anyType – use as DOM tree - CreationConstraints Namespace prefixes in XPaths meaningless Need for WSDL and interpretation for xs:all, xs:choice, and friends

24. Dominic Battré - On the Use of SLAs in AssessGrid 24 Current Implementation Status Grid Portal - First prototype deployed at ATOS (Spain) Brokers Historical Database - Stores historical SLA information from providers - Provider and SLA Offer tables populated – sufficient to support basic confidence measure queries. Confidence Service - Allows querying the reliability of a providers SLA offer - Deployed as WSRF service on the White Rose Grid (UK) Consultant Service - First prototype deployed as WSRF service at PC2 (Germany) - Uses monitoring information by Ganglia Negotiation Manager - First prototype as WS-Agreement service - Supports template validation