First, each machine that has the special software installed needs to advertise its availability in its machine ClassAd . Second, the job identifies in its submit description file that it requires a machine that has the special software.

A machine advertises the presence of special software in its local configuration file, as in this example:

HAS_MY_SOFTWARE = True

Also, if STARTD_ATTRS is already defined in that file, add HAS_MY_SOFTWARE to the list. If STARTD_ATTRS is not already in that local configuration file, add the line:

STARTD_ATTRS = HAS_MY_SOFTWARE, $(STARTD_ATTRS)

For this configuration change to take effect, the condor_startd on that machine needs to be reconfigured. Use condor_reconfig -startd . Each machine with the configuration change must be reconfigured.

Double check that this has been correctly implemented by running the condor_status command:

condor_status -constraint HAS_MY_SOFTWARE

Jobs that need to run on the machines with the special software installedadd a Requirements command to their submit description file:

Requirements = (HAS_MY_SOFTWARE =?= True)

Be sure to use =?= instead of == , so that if a machine does not have the HAS_MY_SOFTWARE configuration variable defined, the job's Requirements expression will not evaluate to Undefined , preventing the job from running anywhere.