User ssh key on RHEL6 system

I have a user id that is used for monitoring (monsvc). All the hosts that it monitors have a key configured so that the monitoring solution can log in to them to run perf commands.

We have our terminal programs (i.e. putty) set up with a key to be able to login to the target hosts as the monsvc user.

I need to set up another linux host so that it can login to hosts as the monsvc user. What do I need to do on the source host in ~/.ssh?

Thanks