= Requirements =

== Example Limiting where a Job runs ==

Condor has a flexible mechanism to specify requirements for a job. In a condor submit file you can add arbitrary restrictions using the requirements option. For example you can restrict a job to run on a specific machine with something like:

{{{
requirements = (Machine == "myogenin.cacr.caltech.edu")
}}}

The requirements field is a boolean expression that can be joined with && (and) and || (or), so if you wanted to do two machines you should be able to do:

{{{
requirements = ((Machine == "myogenin.cacr.caltech.edu")||(Machine == "pongo.cacr.caltech.edu"))
}}}

Because the requirements field is added to other filters generated by Condor its usually a good idea to parenthesize your expression.

== Test Expressions ==

You can discover what variables are exported by a host by doing condor_status -long <hostname>

You can test your requirements expression to make sure its limited to the systems your interested in by doing:

{{{
condor_status -constraint "(expression)"
}}}

(for example)


{{{
condor_status -constraint '(Machine == "pongo.cacr.caltech.edu")'
}}}