1 Workshop 20: Teaching a Hands-on Undergraduate Grid Computing Course SIGCSE The 41st ACM Technical Symposium on Computer Science Education Friday March 12, 2010 Dr. Barry Wilkinson University of North Carolina Charlotte Dr. Clayton Ferner University of North Carolina Wilmington © 2010 B. Wilkinson/Clayton Ferner SIGCSE 2010 Workshop 20 Modification date: Feb 17, 2010 GridNexus workflow editor 8:50 pm - 9:35 pm

Presentation (15 mins) GridNexus demonstration/hands-on experience (40 mins) 8:30 pm - 9:25 pm 2 GridNexus workflow editor

What is GridNexus GridNexus is a GUI that allows the user to create/edit/run workflows Based on Ptolemy II Ptolemy provides the GUI and workflow features. We have extended it to provide the functionality we want (JXPL and GridServices) Release 2.0 download available 3

Getting Started Download from Follow instructions for installation Run GridNexus Choose File->New ->Workflow 4

Getting Started The main frame on the right is the palette for building workflows The upper left frame provides the library of modules The lower left frame is a thumbnail of the entire workflow 5

The Basics Sources produce data without needing input Sinks consume data but may have side effects (such as displaying results) All workflows must start with sources and end with sinks 6

Simple Example 1 Click and drag the “Const” source to the workflow. Click and drag the “JxplDisplay” sink to the workflow 7

Simple Example 1 Double-click on the Const module Change its value to 10 Click commit The new value is shown on the icon 8

Simple Example 1 Input ports are on the left-hand side and output ports are on the right-hand side of each module Click and drag from the output port of the Const module to the JxplDisplay 9

Simple Example 1 A link (or relation) is created between the two modules The output of Const is consumed by the JxplDisplay 10

Simple Example 1 Click on the run button ( ) The JxplDisplay evaluates the input and produces a display window to show the results. 11

Simple Example 2 Transformers are modules that take input, transform it, and produce new output This example computes the express: (23 + 6) ∙ -2 12

The Prog The Prog (short for Program) module allows one to execute separate workflows where it is not desirable to have a relationship between them (i.e. synchro- nization rather than data dependency) 13

The Prog The Prog primitive evaluates each of its inputs in turn It returns the results of the last one evaluated (in this case this case it returns 2x). 14

GridExec (GRAM Client) The GridExec module will run an application on a service using GRAM The Factory Contact is the URL of the server If a Simple command is given, GridExec will construct an RSL file to run it 15 /bin/echo Hello world from GridNexus ${GLOBUS_USER_HOME}/stdout ${GLOBUS_USER_HOME}/stderr

Grid Services First, you need the jars of the Grid Service. E.g.: edu_uncw_math_mathservice.jar edu_uncw_math_mathservice_stubs.jar These are found in $GLOBUS_LOCATION/lib on the server Put in $GRIDNEXUS_HOME/lib (Linux) or C:\Program Files\GridNexus2.xx\lib (Windows) You will need to restart GridNexus so that it will reset the classpath 16

Grid Services The WSRF Client module can serve as a general purpose client for a Grid Service given the following:  URL of the Factory  Class name of the Addressing Locator class 17

Grid Services The icon is set with the name of the service Ports are added for the methods of the service 18

Grid Services In order to call a method that takes no parameters, pass a value of “void” (including double quotes) 19