”Gridification of Web Services Orchestration” CERIST, Networks Division, Mrs A.Elmaouhab Mrs F.Medjek 1

 The scientific computing applications that require large computational and storage resources require computing environments called GRID. These environments are based on Grid service-oriented approaches. In this context,web services infrastructure in the field of scientific computing can be used for applications ”development” and "gridification". This approach requires a study of the two environments and their interaction.  Moreover, service-oriented architectures that use the GRID services infrastructure allow invocations of services across networks and parallel executions as workflows that define them. The orchestration of activities / processes designated by the workflow is essential. It is requested, as part of this work to study the development environments that best meet this constraint (combine Grid and Web services orchestration environments). 2

 Web Services technology provides software developers with a wide range of tools and models to produce innovative distributed applications.  Service orchestration (or composition) has attracted significant interests from both industrial and academic organizations.  Interactions should be driven by explicit process models > BPEL  Business Process Execution Language (BPEL), short for Web Services Business Process Execution Language (WS-BPEL) is an OASIS standard executable language for specifying interactions with Web Services. Processes in Business Process Execution Language export and import information by using Web Service interfaces exclusively.  By using BPEL to define processes, companies can select processes and services to incorporate into their operations. This provides flexibility to replace or upgrade certain aspects of a process without impacting the systems that are working well. 3

BPEL engines comparaison ProductProduct PageVendorEditionRelease DateFramework Compatibility License ActiveVOS Active Endpoints7.0September 2009Servlet or Java EE WS-BPEL; BPEL4People / WS-HumanTask; standards Commercial Apache ODE ASF 2.0-SNAPSHOT August June 2006 Apache Axis Java EE BPEL4WS 1.1, WS-BPEL 2.0 ( WS-HumanTask with Apache HISE ) Apache BizTalk Server MicrosoftBiztalk 2006 R2April 3, 2006.NETBPEL, BPMN, RFIDcommercial iBolt ServerMagic Software Enterprises Java EEBPEL4WScommercial jBPM jBoss January 2009Java EEWS-BPELLGPL Open ESB Sun Microsystems2.010 February 2009Java EE, JBIWS-BPEL 2.0 Open Source, CDDL Oracle BPEL Process Manager Oracle Corporation Jan 2006Java EEWSBPEL 1.1commercial OW2 Orchestra OW October 2009 Apache Axis Apache Axis Apache CXF OSGi Java EE WS-BPEL 2.0LGPL Petals BPEL Engine Petals Link December 2009Java EE WS-BPEL 2.0, WSDL 1.1 and 2.0 LGPL SAP Exchange Infrastructure SAP AG3.0BPELcommercial Virtuoso Universal Server OpenLink Software UDDI, WS-BPEL, WS-* GPL and commercial WebSphere Process Server IBM September 2006Java EEWS-BPELcommercial 4

 Orchestra is a WS-BPEL compliant web services orchestration solution. It organizes web services calls following a process description written in the BPEL XML grammar. It provides a fully Open Source Solution with a BPEL 2.0 compliant engine and an administration console  Orchestra provides Web Service support using the Axis 1.4 framework or the CXF framework  Orchestra is persistable. This means that all the data concerning the processes definition and instances execution is stored in a Database using a persistence framework (hibernate by default). 5

Hardware  A 1GHz processor is recommended, with a minimum of 512 Mb of RAM. Windows users can avoid swap  file adjustments and get improved performance by using 1Gb or more of RAM Software  Orchestra requires Java Development Kit (JDK) 1.5 (also called JDK 5.0) or higher  Orchestra requires Apache Ant or higher 6

 Unzip the orchestra-tomcat distribution package.  A new directory orchestra-tomcat will be created. It contains an ant file to install and start Orchestra.  To install Orchestra, go to orchestra directory and launch the install by running ant.  The install script installs Tomcat and Orchestra. 7

 The default configuration of Orchestra uses the Database persistence service and the H2 Database.  Orchestra has also been tested with Oracle, MySQL and Postgres database systems.  To change to mysql, postgres or Oracle, we need to put the corresponding JDBC driver in the directory $CATALINA_BASE/lib and modify the hibernate.properties file. 8

 Orchestra can run in a clustered environment. In this case, all Orchestra nodes share the same database.  When a process is deployed in Orchestra, the process web services are deployed on each node of the cluster. An instance of the process can be executed on any node of the cluster.  In a clustered environment, reply activities are not supported. The web services exported by Orchestra are only one-way web services. 9

 Orchestra cluster configuration is done by declaring the cluster nodes in the environment.xml file.  To declare a cluster, we add these lines to the environment-factory part of the configuration file:  Each jmx-server element describes an Orchestra node. The serviceUrl and objectName attributes are the parameters to use to connect to the JMX interface of the node. These values are configured for each node in the orchestra.properties file. 10

 Orchestra is a webapp that can be deployed on Tomcat. So starting Orchestra in fact starts Tomcat with the correct environment. This can be performed from the installation directory with the following command line : >cd orchestra-tomcat >ant start  Starting Orchestra will not be done in background. This means that the console starting Orchestra will be dedicated to the traces from Orchestra. To perform further actions, new consoles need to be opened.  To stop Orchestra, type the following command line : >cd orchestra-tomcat >ant stop 11

 Once Orchestra is started, it is then possible to deploy a new process on the engine : >ant deploy -Dbpel=.bpel -Dwsdl=.wsdl - Dextwsdl=  Orchestra also provides the possibility to use an archive to deploy a process. This archive should be a zip file with the extension.bar. Here is the command line to deploy such an archive : >ant deploy -Dbar=.bar 12

 The archive should be a zip file structured as described bellow : /.bpel /.wsdl  To undeploy a process, use the following command line : >ant undeploy -Dprocess= 13

 A command to check the status of Orchestra. This command tells if the engine is started and if so, gives the names of processes deployed on the engine : ant status  A command to simulate a Web Service call. This command will simulate a WS call to interact with a deployed process : ant call -Dendpoint= -Daction= - Dmessage= Other commands 14

Gridification  The focus of the BPEL language is to enable the composition of basic web services into more complex applications. Its popularity in the business application domain makes BPEL very promising for process creation in the Grid domain.  Several works used the web services orchestration in grid envronment such as:  Graphical Composition of Grid Services (Kenneth J. Turner and Koon Leai Larry Tan) wich uses the ActiveBPEL engine becoming commercial.  Grid Service Orchestration Using the Business Process Execution Language (BPEL) (Wolfgang Emmerich1,jj, Ben Butchart1, Liang Chen1Bruno Wassermann1 and SarahL.Price). They describe experience in orchestrating scientific workflows using BPEL. They have gained this experience during an extensive case study that orchestrates Grid services for the automation of a polymorph prediction application. 15

 We used the gLite middleware, which includes the software and packages used for grid implementation.  We installed the prerequisits (JDK ant Apache Ant) and then the orchestra engine in the Computer Element  We run the tests and examples given with orchestra engne. 16

 We have to modify ant configuration in order to run when system boot.  We also have to start orchestra if the system reboot.  We have to define a JDL file to submit job to deploy process in the engine.  Try to see solution to interactive process in the JDL (use interactive jdl !).  Define an application to deploy in the engine in the grid.  Install the engine in differents CEs. Features 17

Question ? 18