HTCondorWiki: Avoiding Black Holes

 {code}
 job_machine_attrs = Machine
 job_machine_attrs_history_length = 5
-requirements = target.machine =!= MachineAttrMachine1 && target.machine =!= MachineAttrMachine2
+requirements = target.machine =!= MachineAttrMachine0 && target.machine =!= MachineAttrMachine1
 {endcode}