Download - A Fault Tolerance Concept for Distributed OSGi Applications - Fabian Meyer

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

OSGi Alliance Community Event 2011© 2008-2011. All Rights Reserved

Agenda

• Motivation

• Related Work

• Approach

• Evaluation

• Conclusion

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

OSGi Alliance Marketing © 2008-2011 . All Rights Reserved

Requirements

• No modification of the underlying OSGi framework

implementation

• Transparency for service consumers

• Administration interface

• Configurable redundancy mechanisms

• Synchronization of replicas


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


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


Architecture


Configuration Setup


Runtime


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


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

Performance Evaluation (2/2)


4,1 ms

4,1 ms

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



Thank you for your attention!

Questions?

References


[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)

Download - A Fault Tolerance Concept for Distributed OSGi Applications - Fabian Meyer

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