rsh

    One last detail deserves our attention: the .rhosts file. As you are
probably beginning to figure out, the .?????? files are used in UNIX to
specify the default behavior of UNIX commands. Such is the case for .rhosts.
My .rhosts file looks like this:
        voodoo.ucsb.edu chris
        whizbang.ucsb.edu chris
        humdinger.ucsb.edu chris
     
    The format of this file is straight forward. Each line contains the name
of a host followed by a username. These entries allow the specified users, on
the specified machines, to log in as you. Note that the host names must be
fully specified. Around here that almost always means something like
    
        MACHINE_NAME.geog.ucsb.edu

    You should be cautious about adding other people to your .rhost file.

pdsh -l/-V可以看到使用的是那个module，rsh/ssh/..