High-level Composition of QoS-aware Grid Workflows: An Approach that Considers Location Affinity...

High-level Composition of QoS-aware Grid Workflows: An Approach that

Considers Location Affinity

Ivona Brandic, Sabri Pllana, Siegfried Benkner

Institute of Scientific Computing (ISC)University of Vienna

Austria

The Workshop on Workflows in Support of Large-Scale Science (works06) In conjunction with HPDC 2006, June 20, Paris, France

Ivona Brandic works06, HPDC06

ProjectInvolvement

Quasi-real time neurosurgery support

Maxillo-facial surgery support

Radiosurgery: Neurosurgery support

Inhaled drug delivery simulation

Advanced Models, Applications and Software Systems for High Performance Computing

http://www.vcpc.univie.ac.at/aurora

http://www.gemss.de/


Motivation

CT image reconstruction

Maxillo facial surgery simulation

QoS specification:time, price

maxTime = 5 hprice = 20 €



MotivationQoS specification:time, price

maxTime = 5 hprice = 20 €

Legal and securityaspects: „Location affinity“

CT image reconstruction


Maxillo facial surgery simulation


Outline

• BPEL extensions for the specification of „location affinity“ (QoWL)

• Use cases for „location affinity“• UML-based Domain Specific Language (DSL) for QoS-

aware Grid workflows• System architecture• Case study• Conclusion


QoWL Code Example

<qowl-element name=„activityName“ portType=„...“ wsdl=„...“ ...>

...

<qos-constraints reqDescVar=„...“ ...>

<qos-constraint name=„beginTime“ value=„...“ weight=„...“ />

<qos-constraint name=„endTime“ value=„...“ weight=„...“ />

<qos-constraint name=„price“ value=„...“ weight=„...“ />

<qos-constraint name=„geographicAffinity“ value=„...“ />

<qos-constraint name=„gridSiteAffinity“ value=„...“ />

...

</qos-constraints>

</qowl-element>

any QoWL element any QoWL element

QoS extension of a BPEL elementQoS extension of a BPEL element


Types of Location Affinity

• Grid site - gridSiteAffinity– Security, law, performance reasons

• Organisation - organisationAffinity– Hide business information from competitors– Sensitive business data

• Geographical region - geograficAffinity– Legal requirements – Electronic transfer of medical data – Medical studies including demographic data


Specification of Location Affinity

A1A1

A2A2

A3A3

A4A4

A6A6

A5A5

A7A7

A8A8

A9A9

A10A10 A11A11

A12A12

A13A13

A14A14

A15A15

G1

G2

G3

<qowl-element name=„A3“ ...> ... <qos-constraints ...> <qos-constraint name=„gridSiteAffinity“ value=„SID“/> </qos-constraints></qowl-element>

<qowl-element name=„A11“ ...> ... <qos-constraints ...> <qos-constraint name=„geographicAffinity“ value=„GID“/> </qos-constraints></qowl-element>

<qowl-element name=„A7“ ...> ... <qos-constraints ...> <qos-constraint name=„organisationAffinity“ value=„OID“/> </qos-constraints></qowl-element>


UML Modeling of QoS-aware Grid Workflows

• XML based workflow specification – error-prone and difficult for end users– Improvement by using a visual and intuitive modeling

language e.g. UML

• High level modeling based on UML– Activity diagrams– Visual modeling of QoS-aware Grid workflows– UML extensions mechanisms – Stereotypes and tagged values– UML based Domain Specific Language (DSL)


Customizing UML for Modeling of QoS-aware Grid Workflows

<<metaclass>>Action

<<stereotype>>Invoke

portType: Stringwsdl: Stringoperation: StringinputVar: StringoutputVar: StringqosConstraints: QTypes

<<invoke>>Start

{ portType = appex wsdl = http://bridge:9355/SPECT/appex?wsdl operation = start inputVar = startRequest qosConstraints= qti:QTypes }

Definition of DSL e.g. Invoke Element

Usage of Invoke Element

UML based modeling of QoS-aware Grid workflows

A1A1 A2A2

A3A3 A4A4

„plain“ UML

StartStart

<<invoke>>Start

<<invoke>>Start

Stereotype Base Class Tags Description

Process «Process»

Activity qosConstraints:QType,variables:VType

Indicates that Activity represents a workflow process

Invoke«Invoke»

Action qosConstraints:QType,portType:String,operation:String,inputVar:String,outputVar:String,wsdl:String

Indicates that Action represents the operationInvocation of an external Grid Service

Copy«Copy»

Action From:FromTypeTo:ToType

Indicates that Action represents the data valueassignment

Sequence«Sequence»

SequenceNode qosConstraints:QType Indicates that SequenceNode represents a series ofactions which are executed sequentially

Flow«Flow»

StructuredActivityNode qosConstraints:QType Indicates that SequenceNode represents a set of Actions which may be executed concurrently

Receive«Receive»

AcceptEventAction portType:String,operation:String,variable:Stringwsdl:String

Indicates that AcceptEventAction represents a blocking message receive

Reply«Reply»

SendSignalAction portType:String,operation:String,variable:Stringwsdl:String

Indicates that SendSignalAction represents the replymessage to a message that was received through a«Receive»

Switch«Switch»

DecisionNode qosConstraints:QType Indicates that DecisionNode represents the conditionalexecution

While«While»

LoopNode condition:Boolean Indicates that LoopNode represents a while loop. Theloop body is executed until the condition is violated.


QoWL Representation with the UML-based DSL (I)

A1A1 A2A2

<<Switch>>SampleSwitch

<<Switch>>SampleSwitch<<Switch>>

SampleSwitch

{qosConstraints = qtiQTypes}

Aggregation function <<Switch>>:

time = Max {time(Bi)| i=1,..,k}

price = Max {price(Bi)| i=1,..,k}

Switch

[case condition] [otherwise]

A1A1

<<Process>>SampleProcess

<<Process>>SampleProcess<<Process>>

SampleProcess


Process


A1A1

A2A2

A3A3

<<Sequence>>SampleSequence

<<Sequence>>SampleSequence<<Sequence>>

SampleSequence


<<Sequence>> Aggregation function:

time = ∑ time(Ai)i=1

n

price = ∑ price(Ai)i=1

n

A1A1 A2A2

<<Flow>>SampleFlow

<<Flow>>SampleFlow<<Flow>>

SampleFlow


<<Flow>> Aggregation function:

time = Max {time(Ai)| i=1,..,n}

price = ∑ price(Ai)i=1

n

SequenceFlow

QoWL Representation with the UML-based DSL (II)


QoS-aware Grid Workflow System

QoS-aware Grid Workflow Engine (QWE)

XML parser / unparser

XML parser / unparser

QoSNegotiator

QoSNegotiator

QoSExecuter

QoSExecuter

WF Planner(static/dynamic)

WF Planner(static/dynamic)

Service Deployerand Generator

Service Deployerand Generator

Grid Infrastructure

TomcatTomcat Apache AXISApache AXIS

QoS-awareVGE Services

Service 1Service 1 Service nService n...

nonVGE Services

Service 1Service 1 Service nService n...

Teuta

GUIGUI

ModelTraverser

ModelTraverser

ModelCheckerModel

Checker


Specification of MFSS Workflow


Generated MFSS Code<sequence name="FEM_Sequence">... <copy name="CID"> <from part=“CID" variable=“getCIDRequest"/> <to part=“CID" variable=“uploadOperation"/> </copy> ... <invoke inputVar="CID" name="StartOperation" operation="start" portType="ApplicationExecutor"> <qos-constraints ReqDesc="maxilloReqDescVar"> <registry wsdl="http://gescher.univie.ac.at:9357/registry/reg?wsdl"/> <registry wsdl="http://kim.univie.ac.at:9357/registry/reg?wsdl"/> <registry wsdl="http://aurora.tuwien.ac.at:9357/registry/reg?wsdl"/> <qos-constraint name="beginTime" value="2006-02-02T16:00:00.000+02:00“ weight="0.3"/> <qos-constraint name="endTime" value="2006-02-02T18:00:00.000+02:00"/> <qos-constraint name="price" value="15" weight="0.7"/> <qos-constraint name="geographicAffinity" value="AT"/> </qos-constraints> </invoke> <invoke name="DownloadOperation“ ... /> ... </sequence>


Related Work

• Languages– BPEL – GPEL– GSFL– SWFL– WSFL– (X)Scufl– AGWL– …

• Projects– BioOpera– Chimera– DAGMan– DiscoveryNet– FreeFluo– Grid ANT– Gridbus– JOpera– Kepler– LEAD– Pegaus– Taverna– Teuta– Triana– …


Conclusion and Future Work

• Workflow execution should meet users requirements– Developed QoS extensions for BPEL– Developed the concept of „location affinity“– Performance, economical, security and legal QoS

• Simplification of workflow specification– Based on UML standard– Developed DSL for QoS-aware Grid workflows

• Validation through specification of a real world workflow• Future work

– Optimization and adaptivity issues

High-level Composition of QoS-aware Grid Workflows: An Approach that Considers Location Affinity...

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