On the Use of Service Level Agreements in AssessGrid
Dominic Battré - On the Use of SLAs in AssessGrid 2
Overview
• Motivation AssessGrid
• Negotiation Scenarios
• End-user Layer
• Broker Layer
• Grid Fabric Layer
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Motivation AssessGrid
• AssessGrid Aim- integrate a risk-aware Service Level Agreement model
into current Grid technology
• Risk awareness incorporated across three layers
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What is risk?
• Risk:Combination of the probability of an event and its consequences
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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
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Why risk management?
low riskmiddle riskhigh risk
• Grid Resource Provider- estimates the risk for agreeing an SLA
- considers risk of resource failure for scheduling
- initiates precautionary fault-tolerance mechanisms
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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 PoF PoF
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Why risk management?
• End User?!?
• is happy…- Knows its risks.
- Can pick most suitable provider!
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Scenario 1: User – Provider Neg.
Get Template
Fill Template- Job description- Max. PoF- Min. Penalty
Create Offer- Set Price
SLA Request
SLA Offer
CommitContract
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Scenario 2a: Broker = Mediator
Template Subscription
Get Templates
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Scenario 2a: Broker = Mediator
SLA Request
SLA Offer
Evaluate Reliability
Medium PoF Low PoF1000 EUR, 1% 1000 EUR, 1.5%
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Scenario 2a: Broker = Mediator
Commit
Timeout
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Scenario 2b: Broker = Contractor
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Architectural Overview
• End-user- Portal
• Broker- Risk Assessor
- Confidence Service
- Workflow Assessor
• Provider- Negotiator
- Scheduler
- Risk Assessor
- Consultant Service
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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
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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
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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
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Summary
• Motivation AssessGrid
• Negotiation Scenarios
• End-user Layer
• Broker Layer
• Grid Fabric Layer
• Questions
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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.
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