How do I implement this? run scheduler on one of cluster?

Hello all,
How do I implement this? run scheduler on one of cluster?
I now have a requirement, needs to run scheduler on one of cluster?,
my app is monitor app, user will specify rules on my apps, like say,
invoke jmx function, find out the connection pools' count, if > 10,
then invoke some function. Something like that, and needs to run/check
every 3min.
So like say, rule1, run every 3min, rule2, run every 5min,
how do I ensure that I only run in one machine of my server cluster(my
monitor cluster)?
my monitor cluster will follow the standard rails deployment, deploy
multiple instances,
on multiple machines.

You should code your own daemon that kicks of every min or so and this
daemon picks-up jobs and finishes these and marks them done. I think
there was a screen cast over with Ryan that shows how to implement a
simple daemon. (This way you can have multiple daemons.. )

Or you could use something like backgrounDrb as a scheduler...