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QoS global management & integration with functional management. LAAS-CNRS Amsterdam meeting 19-21 November 2007. Outline. Local management vs. Global management Stateless vs. Stateful service management Integration of QoS Management and Functional Management. Local vs. Global (1/4):.
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QoS global management & integration with functional management LAAS-CNRS Amsterdam meeting 19-21 November 2007
Outline • Local management vs. Global management • Stateless vs. Stateful service management • Integration of QoS Management and Functional Management
Local vs. Global (1/4): • Monitoring & Measurement • Local • 1Log / Provider & all its Requesters • Global: • 1Log / workflow Asynchronous (one-way) T2 T1 BD1 Asynchronous (one-way) T2 T1 BD QoS Manager1 WS1 WS2 QoS Manager2 QoS Manager1 WS1 WS2 QoS Manager2 T2’ T1’ T2’ T1’ • Global: • We consider QoS parameters involving several requests/responses in the same work flow: • Response time= T2’-T1, Execution time= T1’-T2, etc… BD2 • Local: • We consider only QoS parameters related to single request
WS2 WS1 Req1 Tresp2 Tresp1 WS1 WS2 Req1 Tresp1 Tresp2 Local vs. Global (2/4): • Diagnosis & Repair Planning • Local: • We consider only Diagnosis of QoS parameter values related to single request/response • Example : interlocked web services Sequence diagram • Diagnosis-WS1: • (Tresp1>>Tresp1Avg) ==> WS1 QoS degradation • Repair Planning-WS1: • Substitute (WS1,WS1’) [WS1’equivalent to WS1] • Diagnosis-WS2: • (Tresp2 >> Tresp2Avg) ==> WS2 QoS degradation • Repair Planning-WS2: • Substitute (WS2,WS2’) [WS2’equivalent to WS2]
Local vs. Global (3/4): • Diagnosis & Repair Planning • Global: • We consider 1 Diagnoser and 1 Repair planner for all service in workflow • Diagnosis-WS1&&WS2: • (Tresp1>>Tresp1Avg) && (Tresp2 >> Tresp2Avg) ==> Error detection • QoS degradation on Interlocked services: WS1 and WS2 • ==> WS2 QoS degradation (WS1 degradation is due to degradation propagation) • Repair Planning-WS1&&WS2: • Substitute(WS2,WS2’) [Where: WS2’equivalent to WS2]
Chronicles examples for Global Diagnosis • Messages: • message Tresp1Violation • message Tresp2Violation • message Tresp1OK • message Tresp2OK • Triggering time condition: • Tresp1Violation : Tresp1>(AVGTresp1+delay) • Tresp2Violation : Tresp2>(AVGTresp2+delay) • Tresp1OK : Tresp1<=(AVGTresp1+delay) • Tresp2OK : Tresp2<=(AVGTresp2+delay) • Events: • Event(Tresp1Violation, t0) • Event(Tresp2Violation, t1) • No Event of type TexecOK between t0 and t2 • NoEvent(Tresp1OK,(t0,t1)) • NoEvent(Tresp2OK,(t0,t1)) • Temporal constraints between instants : • t0<t1
Stateless/Stateful (1/2) • Stateless: does not record previous interactions and each interaction request has to be handled based entirely on information that comes with it. • Stateful: remembers preceding events in a given sequence of interactions with another service
Stateless/Stateful (2/2) • BPEL manages states thanks to additional information inserted in the SOAP Header. • Issues: • When rerouting request, we have to reroute Header data responsible of managing states (MessageId, RelatedTo, et …) • When rerouting requests to a new provider, we loss the state made with the pervious provider
SH-BPEL & QoS Manager: Integration • Possible architectural integrations of the functional healing prototype (the SH-BPEL) and the QoS manager prototype • Objective: • The simultaneously management of functional faults and QoS degradation. • Tow integration types: • Passive: No interactions between them • Active: Exchanging requests to coordinate healing
QoS Manager reconfiguration assumptions • QoS Manager repair steps During this phase, the provider is temporarily Unavailable!! Transitory phase Permanent phase Time T0 QoS Degradation detection T1 Start class level reconfiguration T2 Start redeployment T3 Terminate redeployment T4 Terminate class level reconfiguration
Passive Integration: I1Transitory phase managed at the behavioral level SH-BPEL and QoS manager are connected but do not interact directly by exchanging requests (no modifications in API Instance-level substitution Transitory LocalShop3 Web Service Client (Shop Client) QoS Manager (including its own monitoring, diag and class-level substitution) Functional healing (including Shop executed within SH-BPEL) LocalShop1 Web Service Class-level substitution LocalShop2 Web Service
Passive Integration: I2Transitory phase managed at the QoS manager itself SH-BPEL and QoS manager are connected but do not interact directly by exchanging requests (no modifications in API Instance-level substitution Transitory LocalShop3 Web Service Client (Shop Client) QoS Manager (including its own monitoring, diag and class-level substitution) Functional healing (including Shop executed within SH-BPEL) LocalShop1 Web Service Class-level substitution LocalShop2 Web Service
Active Integration: I3QoS Manager and SH-BPEL cooperate to exchange information about current repair plan or to ask for reconfiguration. The QoS Manager asks for instance level reconfiguration during transitory phase The functional level modules ask for class-level repair in case of permanent functional fault Instance-level substitution Transitory LocalShop3 Web Service QoS Manager (including its own monitoring, diag and class-level substitution) Functional healing (including Shop executed within SH-BPEL) Client (Shop Client) LocalShop1 Web Service Class-level substitution Permanent functional fault LocalShop2 Web Service Manage transitory phase