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Akhil Sahai. Sven Graupner. Vijay Machiraju. Aad van Moorsel. Hewlett-Packard Laboratories. SPECIFYING AND MONITORING GUARANTEES IN COMMERCIAL GRIDS THROUGH SLA. IEEE/ACM International Symposium on Clustering Computing and the Grid 2003. Presented by: Yun Liaw. Outline. Introduction - PowerPoint PPT Presentation
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SPECIFYING AND MONITORING GUARANTEES IN COMMERCIAL
GRIDS THROUGH SLASven Graupner
Vijay Machiraju Aad van Moorsel
IEEE/ACM International Symposium on Clustering Computing and the Grid
2003
Akhil Sahai
Presented by: Yun Liaw
Hewlett-Packard Laboratories
Outline
Introduction SLA and the Grid Grid Deployment Infrastructure Grid Management Architecture Specifying and Monitoring SLAs Conclusions & Comments
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Introduction
“Best effort” was a sufficient policy for committing resources in academic grid environments
But when we moving into a commercial space, some stricter guarantees must be hold
2 Problems arises: At any given point of time hundreds of SLA may exist, with large
number of metrics to be observed SLA needs formalize representation so that the SLA evaluation can be
automated For a given application context, multiple resource providers and
consumers are involved The SLA management system must have the ability (Grid Proxy) to
combine the distributed states of SLAs, to provide a consolidated view in the embracing application context
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SLA and the Grid
Negotiating a SLA is an exchange (protocol) of messages between user and provider, potentially involving some form of a middleman or broker
SNAP (Service Negotiation and Acquisition Protocol) [11] Designed for distributed systems Three types of supported SLA in SNAP:
Resource acquisition agreements (user’s right to use the resource) Task submissions agreements (inform needed resources of the existence of a
user’s task) Task/resource binding agreement (enabling the task to consume and agreed
quantity of a resource) Not mentioned the quality aspect, and the maintenance of SLA for the
life-span meaning It is important to understand the SLA hosting environment
To understand how SLA may be specified and monitored
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[11] K. Czajkowski, et al., “SNAP: A Protocol for Negotiation of Service Level Agreements and Coordinated Resource Management in Distributed Systems,” JSSPP, 2002
Grid Deployment Infrastructure
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HP’s UDC (Utility Data Center) : Farm A programmable hosting environment for applications
Globus Resource Specification Language (RSL) A language to specify the resources in a grid, including the
resource topology For UDC resource manager to configure resources
In order to protect different farminstances, two types of resourcesare virtualized for farms: Network Resources Storage Resources
Grid Management Architecture7
•OGSA Grid Conceptual Architecture: based on web services (.Net or J2EE based)
SLA management needs:1.Factory and R & D services to find resources based on QoS requirements2.Life-cycle management and manageability services to collect measurement data3.Reliable invocation for controlling resources4.Notification to inform impacted parties
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Grid Management Proxy
Grid Proxy: Corresponding to a particular Grid
deployment infrastructure Interact with each other forming a
Grid management proxy overlay Protocols that grid community
has agreed on proxy communication GRAAP: Grid Resource Allocation
Management GIS: geographic Information
System GASS: Grid Application Support
System GSI: Grid Security Infrastructure
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SLA Definition
Purpose The reasons behind the creation of the SLA
Parties Parties involved in the SLA and their respective roles
Validity Period The valid time of this SLA
Scope The service scope covered in this SLA
Restrictions The necessary steps to be taken for the requested service levels to be
provided Service Level Objectives
The service level that both users and the provider agreed on
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SLA Definition (cont’d)
Service Level Indicators The means by which these levels can be measured
Penalties Describing what happens in case the service provider is unable to meet
the SLO Optional services
Services that are not normally required by the user, but may be an exception
Exclusions Specifies what is not covered in the SLA
Administration Describe the processes created in the SLA to meet and measure its
objectives
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SLA specification
An SLA is specified over a set of data that is measurable Date constraint (start date, end date, nextEvalDate) SLOs
Day-time constraint MeasuredItems: Set of clauses based on measured data
Contains many items evalWhen: the trigger time of this SLO evaluation evalOn: Determine how the sample data is computed for the
evaluation evalFunc: the mathematical function that is expressible in terms
of its inputs and logic
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SLA specification
Example Scenario:
SLO clause: At month-end, the availability of the
farm allocated to the user myASP.com, measured on the myUDC.com from Mon-Fri from 9AM-5PM should be at least 99.9%
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SLA Measurement Protocol
Init: from measurement proxy to evaluate proxy Request: The evaluator site decides the exact
measurement spec and send to the measurement proxy Agreement: The measurement proxy sends this
message if it agrees to the request to the evaluator Start: message from the evaluator to commence the
report Report: actual measurement report Close: termination
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