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= How to Run and Install an application on the nodes =

=== Prerequisite ===

Before going through this tutorial, you should know the basics of writing and running an experiment script (see [wiki:Tutorial/HelloWorld here] and [wiki:Tutorial/HowtoWriteScripts here]).

You should also have installed a disk image with omf on the nodes of the testbed you are using (e.g. "baseline.ndz"). See [wiki:Tutorial/HowToImage "How to install a disk image"].

=== Goal ===

In this tutorial, you will learn a simple way to execute and install an application on the nodes of a testbed.
  
=== The tutorial experiments ===

This first experiment script [attachment:tut_app_1.rb tut_app_1.rb] shows how to execute an application which is already installed on the nodes, such as tcpdump.

This second experiment script [attachment:tut_app_2.rb tut_app_2.rb] shows how to install and then execute an application on the nodes.

These files contain extensive comments that should help you understand the different steps involved.

To run these example scripts, use the following command:

 {{{
  omf exec tut_app_1
  omf exec tut_app_2
 }}}

=== The Results ===

The experiment screen output should then look like [attachment:sb1_2007_11_19_23_19_08-Output.txt this]. And the experiment log file should look like  [attachment:sb1_2007_11_19_23_19_08.log this].

NOTE: For the first example, tcpdump outputs its user message on STDERR and not STDOUT, thus when running this tutorial script, please ignore false error messages such as: "ERROR nodeApp: tcpdump: listening on ath0, link-type EN10MB (Ethernet), capture size 96 bytes"

=== More... ===

If you would like to use the same application but with different parameters (or with parameters that you would like to dynamically change during the course of the experiment), then you should consider using a "prototype" around your application, as explained in [wiki:Tutorial/HowToAppPrototype this other tutorial].