The document discusses research on self-healing service compositions. It identifies faults that can occur in service-oriented architectures due to dynamic binding between unstable components. The researchers contribute an approach to monitor service compositions and recognize changes in context to support self-healing. When faults are detected, the approach utilizes recovery strategies like retry, rebinding or restructuring the composition locally. While the approach helps cope with some errors, the evaluation is limited and does not fully address issues like semantic interoperability and service substitution.

1. Towards Self-healing Service Compositions
Luciano Baresi, Carlo Ghezzi, and Sam Guinea
Presented By:
Md. Mostafijur Rahman
Supervised By:
Asif Imran
Lecturer, IIT, DU

2. Background
 SoA integrates components in unstable and
evolving context.
 Service discovery phase supports flexible and
dynamic components binding.
 Bindings can fail because of dynamicity.
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3. Background (cont..)
 components can export the services
 clients can discover the services that fit quality
requirements
 If discovery phase is done at design time, the
designer selects the services by hand, without
any real broker
 In this case, wrong design choices and the
actual availability of selected services are the
only problems.
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4. Background (cont..)
 If the discovery phase is done at deployment
time, the service broker is used to configure the
application.
 set of services does not change dynamically and
the binding between service requests and actual
services is done once for ever
 introduces the problems associated with
discovery of services
• discovery phase must be postponed to run-time
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5. Research Question
 What are the main faults associated with SoA?
 How to adopt self-healing service composition
in failure or crash of system?
 How to recognize and monitor service
composition according to changing contexts?
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6. Contribution
 Identify and classify the main faults.
 Service composition for monitoring and
recognizing according to changing contexts.
 Characterization of the faulty behaviors.
 make designed compositions become self-
healing systems
 reorganized processes locally by exploiting
single and special-purpose rules that split or
merge the single nodes of the process.
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7. Methodology
 Runtime error discovery
 Defensive Process Design
 Permit to cope with erroneous behaviors
 Timeout error
 Using clause
 Exception occur
 Service run-time Monitoring
 external monitor-service capable of checking whether
functional and non-functional contracts are violated
 Assertion based (pre, post conditions, invariant)
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8. Methodology (cont..)
 Recovery Strategies
 allow a process to continue execution even in case
of faulty behaviors.
 retry
 Rebind (lookup service)
 Restructure (local reorganization)
 the BPEL-like process definition as a direct graph
 graph transformation rules to modify its topology
 predicates on node (invocation) not matched by the
lookup procedure and its neighbors.
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9. Limitation
 does not promote Web services substitution as a
potential option. Web service substitution [5] is
the only option when a component Web service
totally fails to respond.
 partially solve the semantic ambiguities that arise
in service-discovery architectures, but do not
address the problem of interoperability with web
services that may expose the same interfaces but
different interaction protocols .
 System was not well evaluated.
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10. Conclusion
 Exploit probes to monitor execution of
compositions
 Move towards self-healing
 Perform assessment using a case study
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11. References
[1] BEA, IBM, Microsoft, SAP and Siebel. Business Process Execution Language
for Web Services Version 1.1. 2003.
[2] W. Robinson. Monitoring web service requirements. In Proccedings of the
International Conference on Requirements Engineering, 2003.
[3] IBM Corporation. Web Service Level Agreement (WSLA) Language
Specification. 2003.
[4] T. Lehner. Dynamic Reconfiguration of BPEL Processes - Master Thesis -
Politecnico di Milano and Universitat Passau Fakultat fur Mathematik und
Informatik. 2004
[5] Y. Taher, B. Benslimane, M. Fauvet, and Z. Maamar. Towards an Approach
for Web services Substitution. In Proceedings of the 10th International
Database Engineering and Applications Symposium (IDEAS’06), Los Alamitos,
CA, USA, 2006.
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12. Any Question?
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13. Thank You
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