CMSC 818S Grid Computing SNAP A Protocol for Negotiating Service Level Agreements and Coordinating Resource Management in Distributed System Karl Czajkowshi Ian Foster Carl Kesselman Volker Sander Steven Tuecke Binh Viet Nguyen SLA A common means for reconciling two competing demands between users and owners policies To negotiate a service level agreement SLA A resource provider contracts with a client to provide some measurable capacity or to perform a task Types of SLAs Task service level agreements TSLA negotiates for the performance of an activity or task E g A TSLA is created by submitting a job description to a queuing system Resource service level agreements RSLA negotiate for the right to consume a resource Binding service level agreement negotiates for the application of a resource to a task E g an RSLA promising network bandwidth might be applied to a particular TCP socket BSLA associates a task identified by TSLA and the resource capacity by RSLA Community Scheduler Scenario File transfer Scenario The SNAP Agreement Protocol Agreement State Transitions Agreement Meta Language J language Agreement State Transitions S0 SLAs either have not been created or have been resolved by expiration or cancellation of the SLAs S1 The TSLAs and RSLAs have been agreed upon but are not matched with each other S2 The TSLA is matched with the RSLA and this grouping represents a dependent BSLA to resolve the task S3 Resources are being utilized for the task and can still be controlled or changed Agreement Meta Language I c tdead a I SLA identifier c client with whom the SLA is made tdead an expiration time a a specific TSLA RSLA or BSLA description Agreement Meta Language 2 RSLA content I c tdead r R TSLA content I c tdead j T BSLA content I c tdead j B Operations Allocate Identifier Operation getident tdead useident tdead Agreement Operation request I c tdead a agree I c tdead a Set Termination Operation setdeath I tdead willdie I tdead Resource and Task Meta Language Resource metrics Resource composites Resource Alternatives Resource configuration RSLA binding Resource metrics Time metrics e g Wed Apr 24 20 52 36 UTC 2002 Scalar metrics x u expressed in x real valued units u e g 512 Mbytes Max limit m and m specify an exclusive or inclusive upper limit on the given metric m respectively Min limit m and m specify an exclusive or inclusive lower limit on the given metric m respectively Resource composites Set r1 r2 combining arbitrary resources that are all required Typed Set r1 r2 type combining typespecific resources E g x1 bytes x2 bytes s disk Array nxr is an abbreviation for the group of n identical resource instances r r r Complex time varying description Others Resource Alternatives Alternative v r1 r2 differs from a resource set in that only one element ri must be satisfied Configuration Configure a v specifies an arbitrary configuration attribute a should have value v RSLA binding RSLA binding r IB bind specifies requirement r but also says it should be satisfied using RSLA identified by IB Conclusion New model and protocol for managing the process of negotiating resources in a distributed system SNAP defines a general framework within which reservation acquisition task submission and binding of task to resources can be expressed for any resource in a uniform fashion SNAP has not been validated and implemented yet
View Full Document
Unlocking...