invoking functions on a remote machine without erl running

[HP Wei]

Let me first describe an ideal situation:
Suppose 
there are two machines, hp@REDACTED and hp@REDACTED in the network, 
on which there are two erl running.
>From hp@REDACTED, I want to carry out a function Fun on hp@REDACTED
I understand that this can be done by:  
Return = rpc:call(hp@REDACTED, Mod, Fun, Args). 

--------------------
Now, due to some regulations, I could not leave a 
process such as erl on hp@REDACTED 24 hours a day.
So, how do I perform Mod:Fun in this case when
there is no erl running on hp@REDACTED ??

One way I can think of is:
on hp@REDACTED, I can use os:cmd("rsh m2 /path/to/erl") and 
do rcp:call() and then kill the erl job on hp@REDACTED

Any other way ?

What if m2 asks for password when I do 'rsh m2 ...' ?

--HP