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Ludovic Henrio

Paris, 2006-06-08

An Open Source Middleware for the GridProgramming Wrapping Composing Deploying

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Table of Contents

1. Distributed Objects

2. Deployment

3. Monitoring

4. Composing

5. Conclusion

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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

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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)

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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

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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);

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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

JVM

Active Object

Future Object Request

Req. Queue

Thread

v1v2 ag

WBN!

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Collective Communications: Groups

Typed and polymorphic Groups of active and remote objectsDynamic generation of group of resultsLanguage 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

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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

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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

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Table of Contents

1. Distributed Objects

2. Deployment

3. Monitoring

4. Composing

5. Conclusion

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How to deploy on the multiple Grids

Internet

Clusters

ParallelMachine

LargeEquipment

Internet

Job management forembarrassingly parallel application (e.g. SETI)

Internet

Servlets EJBs Databasesenterprise

scientific edge computing

intranet

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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

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> 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

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Same application, many deployments

One Host Local Grid Distributed Grids

Internet

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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

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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

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Peer-to-Peer ComputingModel & 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

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Fault-tolerance in ProActiveRollback-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

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Table of Contents

1. Distributed Objects

2. Deployment

3. Monitoring

4. Composing

5. Conclusion

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IC2D:Interactive Control & Debug for Distribution

• Graphical Visualisation

• Textual Visualisation

• Control and Monitoring

• Job Management

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IC2D: Application Monitoring

Main Features:

- Hosts, JVM,

- Nodes

- Active Objects

- Topology

- Migration

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Table of Contents

1. Distributed Objects

2. Deployment

3. Monitoring

4. Composing

5. Conclusion

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Content

Controller

ProActive Components

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Table of Contents

1. Distributed Objects

2. Deployment

3. Monitoring

4. Composing

5. Conclusion

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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 team @ INRIA)

Execution Time on a cluster

0

100

200

300

400

500

600

700

800

900

0 10 20 30 40 50 60 70nombre de processeurs

tem

ps

(sec

on

des

)

21*21*21

31*31*31

43*43*43

55*55*55

81*81*81

97*97*97

113*113*113

121*121*121

Mesh Size

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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

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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 http://ProActive.ObjectWeb.org

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f3

f1

Structure

ASP

foo

foo

f2

Active(a)

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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

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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, …

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Interactive Composition in IC2D

Content

Composition ViewInstead of

XML ADL

<processDefinition id="linuxJVM">

<jvmProcess class="org.objectweb.proactive.core.process.JVMNodeProcess"/>

</processDefinition>

<processDefinition id=”sshProcess">

<sshProcess class="org.objectweb.proactive.core.process.ssh.SSHJVMProcess"

hostname="sea.inria.fr">

<processReference refid="linuxJVM"/>

</sshProcess>

</processDefinition>

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Perspective for Components - PSE Graphical Composition, Monitoring, Migration

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Perspective for Components - PSE Graphical Composition, Monitoring, Migration