resource selection services for a single job execution soonwook hwang national institute of...

Resource Selection Services for a Single Job Execution

Soonwook HwangNational Institute of Informatics/NAREGI

OGSA F2F RSS SessionSunnyvale, CA, US

Aug 15, 2005

ProvisioningDeploymentConfiguration

Information Services

ServiceContainer

Data Container

Accounting Services

Execution Planning Services

Candidate Set Generator (Work -Resource mapping)

Job Manager

Reservation

RSS Services to be defined

What are the services OGSA-RSS wants to define?

What are the OGSA-EMS Problems?

• According to the OGSA Architecture v1.0 documents– Finding execution candidate locations (CSG)

• What are the locations at which a job can execution?– Selecting execution location (EPS)

• Once where a job can execute is known, where should it actually run?

– Preparing for execution (the focus of ACS and CDDLM-WG)• Deployment and configuration of binaries and libraries,

staging data– Initiating and managing the execution (the focus of BES-

WG)

RSS Problems: Essential, but Challenging

• Defining the interfaces and protocols of the OGSA Resource Selection Services (RSS) is an integral part of the OGSA-EMS architecture, but seems to be very challenging – Interactions with many other OGSA EMS components

• Job Manger (JM), Information Service (IS), Service Container (SC) , Reservation Service (RS) , etc

– Various job types• Single, atomic job• A set of jobs w/o dependency

– e.g., embarrassingly-parallel applications• A set of jobs w/ dependency

– e.g., workflows

Let’s focus on a simple case to identify some interactions between RSS and other EMS Services

• Focusing on resource selection services for the execution of a single, atomic job – A single job that exactly fits into the JSDL v1.0

spec– Not considering complex jobs such as workflows

and embarrassingly parallel applications• JSDL v1.0 specification

– Job identification requirements– Resource requirements– Data requirements

Resource Selection Scenarios

1. JM sends to EPS a JSDL document with a job’s resource requirements written in it

2. EPS hands off the JSDL document to CSG3. CSG creates a candidate set of resources,

returning it to EPS– CSG looks up the Information Service to find resources

that match the job’s resource requirements4. EPS selects the best one among the candidate

resources – EPS perhaps uses some selection policy to select the

best one5. JM submit the JSDL document to the se

Interactions between RSS and other EMS Services

EPS

CSG

Info ServiceService Container

Job Manager

User submits job as abstract JSDLdocument along with selection policy

CSG mightinteract withSC directly

SC publishes information about resource attributes

• Concretized JSDLConcretized JSDL

• Candidate EPRsCandidate EPRs

• Concrete JSDLConcrete JSDL

• EPR to the SCEPR to the SC

• Abstract JSDLAbstract JSDL

• Selection PolicySelection Policy

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Concrete Concrete JSDLJSDL

Abstract Abstract JSDLJSDL

Abstract and Concrete JSDL

• Abstract JSDL– a JSDL document where some of elements

necessary for initiating the execution of a job have yet to be filled

• E.g., a JSDL document with no hostname specified in it

• Concrete JSDL– a self-sufficient JSDL document for job

execution

Job Manager (JM)

• Responsible for managing and controlling of jobs during their entire lifetime

• Submits jobs described in a JSDL document to a Service Container which the EPR returned from EPS points to– uses the protocol and interfaces defined in the

OGSA BES specification

Information Service (IS)

• A placeholder to keep attributes metadata about resources

• Service Containers publish their resource attributes along with their own EPRs to IS– Static information

• Architecture, OS version, Hostname, etc – Dynamic information

• CPU load, Queue length, etc

Candidate Set Generator (CSG)

• Performs a simple, dumb matchmaking with the IS to identify a list of container services that have resource capabilities that meet the job’s resource requirements

• Concretizes the abstract input JSDL document using resource information retrieved from the IS– e.g., might fill in the “CandidateHost” element

• Passes EPRs to candidate hosts and the more concretized JSDL document back to EPS

• Discussion– Should CSG be dumb or intelligent?

• E.g., Should selection policy be reflected in CSG as well when CSG locating candidate resources?

Execution Planning Service (EPS)

• Select the best one among the candidate resources sent from CSG

• If needed (?), may want to interact with the IS to get additional resource information that could be used to more concretize the JSDL document returned from CSG

• Uses the selection policy which is given as input to select the best one

• Discussion– Is it a good idea to allow EPS to interact with IS as well?– What kinds of selection policies should be considered?– Where should selection policy be put, EPS, or CSG, or both?

Selection Policy

• Some user preference or priority to be allowed to put on each of resource requirements specified in the JSDL document– e.g., Condor ClassAD

• Some objective function – e.g., minimum execution time, lowest cost, reservation, etc

• Application-specific selection algorithm• Discussion

– Is working on the Condor ClassAD-like user preference mechanism within this OGSA-RSS-WG as an example of selection policy worth trouble to do?

Reservation Service (RS)

• Will probably reside on local resources, directly interacting with local schedulers (e.g., maui, PBSPro) to get and manage reservations on locally reservable resources

• Will probably provide a common interface– “MakeReservation” – “CancelReservation”

• Maybe some advanced service container could act as the RS by providing such a common reservation interface

Reservation as Selection Policy

EPS

CSG


Job Manager







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RS


• EPR to the SCEPR to the SC(w/ Reservation)

Make Reservation from 21:00 Make Reservation from 21:00 – 23:00 August 15, 2005– 23:00 August 15, 2005



EPS makes reservations

EPS

CSG


Job Manager







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RS

EPS mak

es re

serva

tion(s

)






CSG makes reservations

EPS

CSG


Job Manager






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RS

CSG makes reservations



(w/ Reservation)





EPS confi

rms r

eserv

ation

(s)

Make Reservation Make Reservation from 21:00 – 23:00 from 21:00 – 23:00 August 15, 2005August 15, 2005

Discussions on Reservation Service

• Which one should interact with the RS, EPS, or CSG, or perhaps JM?– How about some kind of a global RS that

interacts with the local RS to make reservation on behalf of either ESP or CSG?

• How does the RS have an effect on the design of EPS and CSG?

Summery of Discussion Topics

• Should CSG perform a simple matchmaking or have some intelligence in locating available resources?

• Is it a good idea to allow EPS to interact with IS as well e.g., to have it concretize the input JSDL document? Is there any use case for this?

• What kinds of selection policy should be considered?• Where should selection policy be put, only EPS, or CSG as well? • Is working on the Condor ClassAD-like user preference mechanism as

an example of selection policy worth trouble to do? • Which one should interact with the local RS, EPS or CSG?• Is it a good idea to regard Reservation as a selection policy?• How about some global reservation service? Do we need it? How

does it affect the interface design of EPS and CSG?• In General, how the RS affect on the design of EPS and CSG?• Any other important issues to discuss together?

Thank you

What is the Architecture

EPS

CSG


Job Manager Reservation Service

User submits jobas JSDL document

CSG gets potentialatomic reservationsfrom reservationservice

CSG retrieves service info(info model not important)

Job Manager asksEPS where to run

EPS asks CSG forcandidate executionplans (concretized JSDL)

EPS commits thereservation(s) to be used

CSG mightinspectservice

containersdirectly

Service container publishes information about itself

JM makes reservations

EPS

CSG


Job Manager



Abstract Abstract

JSDLJSDL


• Candidate EPRsCandidate EPRs Concrete Concrete

JSDLJSDL



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RS

JM m

akes reservations


• EPS to the SCEPS to the SC

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resource selection services for a single job execution soonwook hwang national institute of...

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