Secure Dynamic Reconfiguration of Scalable Systems with Mobile Agents

1. Secure Dynamic Reconfiguration of Scalable Systems with Mobile Agents Fabio Kon, Binny Gill, Manish Anand, Roy Campbell, and M. Dennis Mickunas {f-kon,roy}@cs.uiuc.edu Department of Computer Science University of Illinois at Urbana-Champaign http://choices.cs.uiuc.edu/2K

2. Introduction Network-Centric Operating System: • Facilitate management in modern computing environments • Heterogeneity: embedded sys., PDAs, laptops, workstations • Dynamism: rapid software evolution, mobile users & computers • GOAL: • Facilitate management by building a middleware-level operating system on top of this heterogeneous world

3. 2K Research • Automatic Configuration • based on component prerequisites • Dynamic Reconfiguration • based on component configurators • QoS-aware Resource Management • Security Service • User Environment Service • Data Management Service • Mobile Reconfiguration Agents

4. Motivation • Scope of Internet services is expanding: • e-commerce, banking, news, distance learning, medical applications, active spaces. • Basic requirements: • Scalability • Availability • Software evolution brings an additional requirement: • Dynamic Reconfiguration

5. Dynamic Reconfiguration • Dynamic Reconfiguration is required for 1. changing system parameters at runtime 2. replacing components at runtime: • fixing bugs • updating functionality • adaptation to changes in the environment • Challenge: integrate 3 conflicting requirements (scalability, availability, and dynamic reconfiguration) • Solution: mobile reconfiguration agents

6. Our Approach • 2K services and applications are built on top of the CORBA standard middleware. • But, traditional CORBA was not very flexible. • We created dynamicTAO, a reflective CORBA ORB that supports: • inspection of dynamic software architecture • dynamic reconfiguration of software architecture

7. dynamicTAO • reflective capabilities can be used to • reconfigure the ORB internals, • reconfigure applications that run on top of the ORB. • Our infrastructure for mobile reconfiguration agents is implemented inside dynamicTAO. • So, it is available to any 2K service and application.

8. The 2K Architecture

9. The dynamicTAO Framework

10. Mobile Agents • A mobile agent visits a collection of ORBs. • In each ORB along its path, it can • install new components on the disk, • dynamically link new components, • inspect the state and configuration of the ORB and the applications on top of it, • reconfigure ORBs and applications.

11. A Flexible Framework • Different NetworkBrokers support different agent flavors. For example: • simple, lightweight, script-based agents (carrying data and DCP commands only). • powerful, heavyweight, Java-based agents (carrying data, bytecode, and dynamic state, taking autonomous decisions). • Simple agents are suitable for PDAs, embedded systems.

12. Reconfiguration with Mobile Agents • SysAdmins use a GUI to build agents for • reconfiguration • inspection • GUI is used to 1. Build distribution graph 2. Select reconfiguration and inspection commands 3. Visualize results.

13. Security • SecureAgentBroker uses the GSS-API and supports Role-Based Access Control. • Agents are signed and transmitted via secure connections, using encryption. • RBAC is used in each ORB to decide which commands each agent is allowed to perform.

14. The SecureAgentBroker

15. Experimental Results • Testbed: • Three Ultra Sparcs, Solaris 7 @cs.uiuc.edu • Three 333MHz PCs, Linux RH6.1 @escet.urjc.es • Three 300MHz PCs, Linux RH6.1 @ic.unicamp.br • 100Mbps Fast Ethernet (intra-domain) • Public Internet (inter-domain)

16. Mobile Agents vs.Conventional Client/Server

17. Point-to-Point vs. Distribution Tree

18. Uploading a New Component to 9 Nodes

19. Related Work • Our work was influenced by previous research on: • mobile agent infrastructures • dynamic reconfiguration of distributed systems • object-oriented frameworks • security • Our main contribution was to show how to combine all these results in an integrated architecture.

20. Future Work • Support for fault-tolerance: • fault-recovery when part of the reconfiguration process fails within a node • fault-recovery when the reconfiguration fails in part of the distributed system • New implementation of Java reconfiguration agents based on one of the existing infrastructures. • Deploying agents for reconfiguration of active spaces.

21. Conclusions • Mobile agents is an effective mechanism for reconfiguration of distributed systems, combining scalability and availability with dynamic reconfiguration. • A framework enabling different agent flavors is important for taking agents to devices with limited resources (e.g.PDAs).

22. How to contact us e-mail: {f-kon,roy}@cs.uiuc.edu 2K Web site: http://choices.cs.uiuc.edu/2K

23. Reconfiguration Agents • Code uploading example: upload_impl Connection UDPCon load_impl Connection UDPCon hook_impl >Connection Reflector UDPConnection • Reconfiguration example: configure_impl Reflector “MAX_NUM_CLIENTS=200”

24. Accessing the ORB Reconfiguration Interface 1. Local or remote code through IDL 2. Telnet 3. Java GUI 4. Reconfiguration Agents

25. DOCTORDynamic ORB Configuration Tool