1 Ludovic Henrio Paris, An Open Source Middleware for the Grid Programming Wrapping Composing Deploying

2 Table of Contents 1.Distributed Objects 2.Deployment 3.Monitoring 4.Composing 5.Conclusion

3 A uniform framework: An Active Object pattern A formal model behind: Determinism (POPL’04) Programming Model (Active Objects): Asynchronous Remote Invocations, Wait-By-Necessity Groups, Mobility, Components, Security, Fault-tolerance, Load balancing Environment: XML Deployment Descriptors, File Transfers Interfaced with: rsh, ssh, LSF, PBS, Globus, Jini, SUN Grid Engine Graphical Visualization and monitoring: IC2D In the www. ObjectWeb.org Consortium (Open Source LGPL) ProActive : A Java API + Tools for Parallel, Distributed Computing

4 Model Activity : coarse-grained structuring entities (subsystems) possibly owns many passive objects has exactly one thread, and one active object. No shared passive object -- Parameters are passed by deep-copy Asynchronous Communication between active objects Futures (promised replies) and wait-by-necessity. JVM copy! distant.foo(object )

5 An object created with A a = new A (obj, 7); can be turned into an active and remote object: Object-based: a = (A)ProActive.turnActive (a, node); Instantiation-based: A a = (A)ProActive.newActive(«A», params, node); The “node” is the AO container. Remaining of the code unchanged  “Transparency” Creating active objects

6 Future: result of a method call A call on an active object consists in 2 steps A request : name of the method, parameters… A Reply : the result of the method call A request returns a Future object which is a placeholder for the result The callee will update the Future when the result is available The caller can continue its execution event if the Future has not been updated Reply future = distant.query (parameters);

7 A Wait-by-necessity Proxy Java Object A ag = newActive (“A”, […], VirtualNode) V v1 = ag.foo (param); V v2 = ag.bar (param);... v1.bar(); //Wait-By-Necessity V Wait-By-Necessity is a Dataflow Synchronization JVM A Active Object Future Object Request Req. Queue Thread v1 v2 ag WBN!

8 Collective Communications: Groups Typed and polymorphic Groups of active and remote objects Dynamic generation of group of results Language centric, Dot notation Manipulate groups of Active Objects, in a simple and typed manner: Be able to express high-level collective communications (like in MPI): broadcast, scatter, gather, all to all

9 A Creating AO and Groups Typed Group Java or Active Object A ag = newActiveGroup (“A”, […], VirtualNode) V v = ag.foo(param);... v.bar(); //Wait-by-necessity V Typed groups, and Asynchrony are crucial for Components and GRID JVM

10 Weak Migration of active objects Migration is initiated by the active object itself through a primitive: migrateTo Can be initiated from outside through any public method The active object migrates with: all pending requests all its passive objects all its future objects Automatic and transparent forwarding of: requests (remote references remain valid) replies (its previous queries will be fullfilled) 2 Techniques : Forwarders or Centralized server

11 Table of Contents 1.Distributed Objects 2.Deployment 3.Monitoring 4.Composing 5.Conclusion

12 How to deploy on the multiple Grids Internet Clusters Parallel Machine Large Equipment Internet Job management for embarrassingly parallel application (e.g. SETI) Internet Servlets EJBsDatabases enterprise scientific edge computing intranet

13 Abstract Deployment Model > Problems : Difficulties and lack of flexibility in deployment Avoid scripting for: configuration, getting nodes, connecting, etc. A key principle: Virtual Node (VN) in XML deployment file Abstract Away from source code: –Machines names –Creation/Connection Protocols –Lookup and Registry Protocols Interface with various protocols and infrastructures: –Cluster: LSF, PBS, SGE, OAR and PRUN(custom protocols) –Intranet P2P, LAN: intranet protocols: rsh, rlogin, ssh –Grid: Globus, Web services, ssh, gsissh

14 > Virtual Node (VN): Identified as a string name Used in program source Configured (mapped) in the XML descriptor file --> Nodes XML Deployment files Program Source Descriptor (RunTime) | | Activities (AO)--> VN VN --> JVMs --> Hosts Runtime structured entities: 1 VN --> n Nodes in m JVMs on k Hosts > Operations specified in descriptors: Mapping of VN to JVMs (leads to Node in a JVM on Host) Register or Lookup VNs Create or Acquire JVMs Security, Fault-tolerance

15 Same application, many deployments One Host Local Grid Distributed Grids Internet

16 Security: Key Features ProActive Security Features Authentication of users and applications (PKI X 509 certificates) Authentication, Integrity and Confidentiality of communication In XML deployment files, Not In Source Mobility Aware Dynamically negotiated policies Easily adaptable to the deployment

17 Pure P2P: Definition Only PEERs, no above everything, top level, server(s) Every peer is, somehow, also a server No master … No slave ! System gets organized dynamically, without static configuration Coherent, desired behavior, dynamically emerges

18 Peer-to-Peer Computing Model & Infrastructure Dynamic Computational Peer-to-Peer (P2P): Intranet & Internet Propose a High Level Model Dynamic JVMs Network (computation nodes) [infrastructure] P2P Programming Model for Branch and Bound (B&B) problems ProActive Context: no modification of Java language, of JVMs, … Inspired from Gnutella Use Sparse CPU Cycles from Desktop Workstations/clusters

19 Fault-tolerance in ProActive Rollback-Recovery fault-tolerance After a failure, revert the system state back to some earlier and correct version Based on periodical checkpoints of the active objects Stored on a stable server Two protocols are implemented Communication Induced Checkpointing (CIC) Low failure free overhead Slow recovery Pessimistic Message Logging (PML) Higher failure free overhead Fast recovery Fault-tolerance is set in deployment descriptors Fault-tolerance service attached to virtual nodes No source code alteration Transparent and non intrusive

20 Table of Contents 1.Distributed Objects 2.Deployment 3.Monitoring 4.Composing 5.Conclusion

21 IC2D: Interactive Control & Debug for Distribution Graphical Visualisation Textual Visualisation Control and Monitoring Job Management

22 IC2D: Application Monitoring Main Features: - Hosts, JVM, - Nodes - Active Objects - Topology - Migration

23 Table of Contents 1.Distributed Objects 2.Deployment 3.Monitoring 4.Composing 5.Conclusion

24 Content Controller ProActive Components

25 Table of Contents 1.Distributed Objects 2.Deployment 3.Monitoring 4.Composing 5.Conclusion

26 Appli: JEM 3D : Java 3D Electromagnetism together with Said El Kasmi, Stéphane Lanteri (caiman) Maxwell 3D equation solver, Finite Volume Method (FVM) Pre-existing Fortran MPI version: EM3D (CAIMAN INRIA) Execution Time on a cluster nombre de processeurs temps (secondes) 21*21*21 31*31*31 43*43*43 55*55*55 81*81*81 97*97*97 113*113* *121*121 Mesh Size

27 ProActive and (De Facto) Standards RMI, RMI-Ibis, Jini, HTTP rsh, ssh, scp Globus GTx, sshGSI, Unicore, EGEE gLite LSF, PBS, OAR, Sun Grid Engine Fractal Components Web Services OSGi

28 That’s it! A Strong Programming Model + A Strong Deployment Presented features: Active Objects, XML descriptors, Security, P2P, Fault-tolerance Features not detailed: OO SPMD, Web Services, load balancing, legacy wrapping, and more… Perspectives: Better Error Management (Exceptions, …) Behavior Specification (Model Checking) Tools for Distributed Programming: Code Analysis, Transformation, Integrated IDE Available in Open Source

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31     f3 f1 Structure ASP foo f2 Active(a)

32 Openness Open Source Easy to extend Add new Deployment Protocols Add new File Transfer Protocols Not so hard to add new Transport (one could imagine hardware specific implementations) Add Checkpointing Protocols Add localization strategies for mobility

33 ASP: Summary and Results An Asynchronous Object Calculus: Structured asynchronous activities Structured communications with futures Data-driven synchronization ASP  Confluence and Determinacy Future updates can occur at any time Execution characterized by the order of request senders Determinacy of programs communicating over trees, …

34 Interactive Composition in IC2D Content Composition View Instead of XML ADL <sshProcess class="org.objectweb.proactive.core.process.ssh.SSHJVMProcess" hostname="sea.inria.fr">

35 Perspective for Components - PSE Graphical Composition, Monitoring, Migration

36 Perspective for Components - PSE Graphical Composition, Monitoring, Migration