A Fault Tolerance Concept for Distributed OSGi Applications - Fabian Meyer
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Transcript of A Fault Tolerance Concept for Distributed OSGi Applications - Fabian Meyer
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COPYRIGHT © 2008-2011 OSGi Alliance. All Rights Reserved
A Fault Tolerance Concept for
Distributed OSGi Applications
Patrick Deuster, Fabian Meyer, Reinhold Kröger
RheinMain University of Applied Sciences
September 21, 2011
OSGi Alliance Marketing © 2008-2010 .
All Rights Reserved
Page 1
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OSGi Alliance Community Event 2011© 2008-2011. All Rights Reserved Page 2
Agenda
• Motivation
• Related Work
• Approach
• Evaluation
• Conclusion
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Motivation
• OSGi is a commonly used service platform
• Distribution supported by Remote Service specification
in R4.2
• Remote Services can be used as a basis for a fault
tolerance concept
• Based on Patrick Deuster’s M.Sc. Thesis [1] at
Wiesbaden University of Applied Sciences
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Requirements
• No modification of the underlying OSGi framework
implementation
• Transparency for service consumers
• Administration interface
• Configurable redundancy mechanisms
• Synchronization of replicas
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Related Work
• DR-OSGi [2] • Aspect oriented
• Caching, redundancy
• Major disadvantage: Can only be bound to local replica
• Towards reliable OSGi framework and applications [3] • Proxy layer
• Service call forwarding to replicas
• Major disadvantage: Modification of the OSGi framework implementation
• FT-OSGi [4] • Proxy layer
• Configuration and synchronisation
• Major disadvantage: No transparency for service consumers
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Approach
• Redundant service instances
• Active and passive replicas
• Proxy layer
• Service call forwarding from proxy to service replicas
• Flexible result evaluation in proxy to determine reply to
caller
• OSGi Remote Service specification used
• Apache Zookeeper used for group communication to
establish consistent views
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Architecture
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Configuration Setup
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Runtime
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Performance Evaluation (1/2)
Configuration Avg (ms) Min (ms) Max (ms) Std. Dev. (ms)
No Fault Tolerance 2,4 1 26 1,3
1 Active / 1 Passive 7,1 4 64 3,6
2 Active / 1 Passive 8,2 4 61 5,6
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Type Avg (ms) Min (ms) Max (ms) Std. Dev. (ms)
Service Instance Failover 11,1 1 30 7,0
Framework Instance
Failover
3881,9 3013 5391 687,7
• Call time (2000 service calls)
• Reconfiguration time (50 failovers)
Setup:
CPU: Intel Core 2 6320
Phys. Mem.: 3 GB
Java: JDK 1.6
OSGi-FW.:
Eclipse Equinox 3.6
RS-Impl.:
Eclipse Communication
Framework
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Performance Evaluation (2/2)
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4,1 ms
4,1 ms
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Conclusion
• Design and implementation of a fault tolerance concept
for distributed OSGi applications • Transparent proxy layer with call forwarding
• Automated replica distribution
• Active and passive redundancy
• Flexible result evaluation in proxy to determine reply to caller
• State synchronization between replicas
• Future Work: • Detailed performance evaluation
• Utilization in real application
• Cooperation with industrial partners
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Thank you for your attention!
Questions?
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References
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[1] Deuster, Patrick. Ein Fehlertoleranzkonzept für verteilte OSGi-Anwendungen. Master Thesis, Wiesbaden University of Applied Sciences (2011)
[2] Kwon, Young-Woo; Tilevich, Eli; Apiwattanapong. Taweesup: DR-OSGi: Hardening Distributed Components with Network Volatility Resilency. In: Middleware (2009), 1-20.
[3] Ahn, Heejune; Oh, Hyukjun; Sung, Chang O.: Towards reliable OSGi framework and applications. In: Proceedings of the 2006 ACM synposium on Applied computing. ACM (SAC ´06).
[4] Torrão, Carlos; Carvalho, Nuno A.; Rodrigues, Luís: FT-OSGi: Fault Tolerant Extensions to the OSGi Service Platform. In: Proceedings of the Confederated International Conferences, CoopIS, DAO, IS, and ODBASE 2009 on On the Move to Meaningful Internet Systems: Part 1. Springer-Verlag (OTM ´09)