Upload
universitaet-rostock
View
783
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Presentation by Karsten at ICSOC 2009 on Nov 27 in Stockholm
Citation preview
Another Approach to Service Instance Migration
Nannette Liske, Christian Stahl, Niels Lohmann, Karsten Wolf
Humboldt Univ. Techn. Univ. University ofBerlin Eindhoven Rostock
Service
Service
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 2
Another Approach to Service Instance Migration
•We consider business services•many internal states•complex interaction•long running
•We consider service models•states•labeled transitions
•send: !x•receive: ?y•internal: τ
•correct = •deadlock free•bounded channels
?c!a
?b•We can translate
BPEL2oWFN
UML2oWFN
oWFN2BPEL
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 3
Another Approach to Service Instance Migration
Why?Long running services may need to be modified ... even running instances
•new legal requirements•new technology•mergers and acquisitions
What?•Freeze old service in some state (preferrably current)•setup new service in fitting state•continue with new service, interacting with the partner(s) of the old one
ChallengeInteracting partners should be able to seamlessly continue interaction
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 4
Another Approach to Service Instance Migration
On formal model:
?c!a
?b?c
?c
!a
?b
τ
τ
τ
Problem statement:Given two services Sold and Snew, compute large set of jumper transitions
where
every correctly interacting partner of Sold is a correctly interacting partner of Sold ⊕ Snew ⊕ J
„Hybrid model“
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 5
Another Approach to Service Instance Migration[Ryu, Casati et al]•compute jumper transitions based on backward (history) and forward (future) traceinclusion•synchronous communication•implicitly assume deterministic models•unique names for the activities
[Rinderle-Ma, Reichert, Dadam]•migrate workflows•consider sequence of elementary modifications (insert/delete activity, change order)•consider data
[van der Aalst, Basten]•compare two workflows using projection inheritance (stricter than our notion)
Our Approach•compute jumper transitions based on reasoning about correctly interacting partners•asynchronous communication•nondeterministic models
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 6
Service ???
?€
?C ?T
!B !B
!€
!C?B
!€
!T?B
!T
!€?B
!C
!€?B
!€!C
?B
!T?B
....!€
!€ !€!T
!T !C
!C
?B ?B
Another Approach to Service Instance Migration
1. Correctly interacting partners
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 7
Service ???
?€
?C ?T
!B !B
!€
!C?B
!€
!T?B
!T
!€?B
!C
!€?B
!€!C
?B
!T?B
....!€
!€ !€!T
!T !C
!C
?B ?B
mostpermissive
Another Approach to Service Instance Migration
1. Correctly interacting partners
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 8
Service ???!€!€ !€
!T
!T !C
!C
?B ?B
!€!C
?B
!T?B
Another Approach to Service Instance Migration
1. Correctly interacting partners
!€!€ !€
!T
!T !C
!C
?B ?B
!€!T?B
mostpermissive
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 9
Another Approach to Service Instance Migration
2. Characterize J
qold ? qnew
Consider Snew ⊕ MPP(Sold)
States....,[qnew,q‘1,M‘1],[qnew,q‘2,M‘2],[qnew,q‘3,M‘3],...,[qnew,q‘n,M‘n],...
⊆
Idea: In the frozen state qold, partner and pending messages are in a situation thatthey could have been in with qnew, had they started with Snew from the beginning.
Consider Sold ⊕ MPP(Sold)
States....,[qold,q1,M1],[qold,q2,M2],[qold,q3,M3],...,[qold,qm,Mm],...
Formally:
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 10
Another Approach to Service Instance Migration
Example 1
?c!a
?b?c
?c
!a
?b
SoldSnew
A
B C
D
MPP(Sold)
?a
?a
!b
!b
⊕?c
!a
?b
[A,a] [B,ab][C,-] [D,b]
[B,a] [D,-]
[A,-] [B,b]
⊕
?c?c
!a
?b
[A,a] [B,ab][C,-] [D,b]
[B,a] [D,-] ∅
[A,-] [B,b]
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 11
Another Approach to Service Instance Migration
Example 2
?d
?e
Sold Snew
?f
!g
?d
?e ?f
!g
?d
Example 3
?h
!i
Sold Snew
!j
?h
!i !j
?h
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 12
Another Approach to Service Instance Migration
Maximality
Computed set of jumper transitions is max if
•services are subsititutable (initial state can be migrated into each other)•want to migrate only into states of Snew reachable with some partner of Sold
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 13
Another Approach to Service Instance Migration
Numbers
Service Sold | Interface | States of Sold States of MPP(Sold)
States of Snew
Travel service 10 34 192 202
Purchase Order 10 402 168 176
Ticket Reservation
9 304 110 118
Internal Order 7 1,516 96 104
Contract Negotiation
11 784 576 588
Deliver Finished Goods
14 182 1,632 1,394
Passport Application
11 14,569 1,536 1,540
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 14
Another Approach to Service Instance Migration
Numbers
Service Sold States Snew⊕MPP(Sold)
Theoretical Search space
| J | time (sec)
Travel service 2,976 3,333,120 49 2.1
Purchase Order 1,031 4,886,940 359 0.6
Ticket Reservation
2,545 19,851,000 429 1.3
Internal Order 1,455 34,460,220 1,613 0.9
Contract Negotiation
17,331 856,844,640 866 12.9
Deliver Finished Goods
60,753 1,050,783,888 197 123.1
Passport Application
100,975 990,199,624,400 22,382 518.1
Tool and examples: http://www.service-technology.org/live/migration/
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 15
Another Approach to Service Instance Migration
Tools related to this presentation
available at www.service-technology.org/tools
•mia compute the jumper transitions
•bpel2owfn translate BPEL to Petri nets•uml2owfn translate UML activity diagrams to Petri nets•owfn2bpel translate Petri nets to abstract BPEL
•wendy synthesize a (most permissive) partner
•sayo compute a public view
and several more
Liske, Lohmann, Stahl, Wolf: Another Approach to Service Instance Migration 16
Another Approach to Service Instance Migration
Conclusion
•approach feasible•implemented•different from existing approaches•can be combined (just intersect the resulting jumper sets)
Next steps
•take care of data dependencies and life cycles•concurrent migration
Another Approach to Service Instance Migration
Nannette Liske, Christian Stahl, Niels Lohmann, Karsten Wolf
Humboldt Univ. Techn. Univ. University ofBerlin Eindhoven Rostock
Service
Service