Suppose two machines are running the same code, but you want to offset the timing of the code being run so that there's no possibility of their not running simultaneously, and by simultaneously I mean not running within 5 seconds of each other.
One could generate a random number of seconds prior to the start of the running code, but that may generate the same number.
Is there an algorithm to independently guarantee different random numbers?
As pointed in comments/other answer true random can't really provide any guarantees of falling into particular ranges when running in parallel independently.
Assuming your goal is to not run multiple processes at the same time you can force each machine to pick different time slot to run the process.
If you can get consensus between this machines on current time and "index" of machine than you can run your program at selected slots with possible random offset withing time slot.
I.e. use time service to synchronize time (default behavior for most of OS for machines connected to pretty much any network) and pre-assign sequential IDs to machines (and have info on total count). Than let machine with ID to run in time slot like (assuming count < 60, otherwise adjust start time based on count; provide enough time to avoid overlaps when small time drift happens between time synchronization interval)
This way no communications between machines is needed.