ssh -p 22 user@host</p> without password as I have set up the ssh key authentication.</p>

<p>When I am using the module <code>Net::OpenSSH::Parallel
##</code><code>##

 0.488| [192.168.24.16] added (HASH(0x19e5f70))
 0.488| [192.168.24.16] state set to done
 0.488| selector(*) --> [192.168.24.16]
 0.488| [192.168.24.16] action command queued
 0.488| [192.168.24.16] state changed done --> ready
 0.488| run: iterating...
 0.488| run: hosts at connecting: 0
 0.488| run: hosts at ready: 1
 0.488| num workers: 1, maximum: 1
 0.488| [192.168.24.16] at_ready
 0.488| [192.168.24.16] at_ready, starting new action command
 0.488| [192.168.24.16] host is not connected, connecting...
 0.488| [192.168.24.16] _connect, starting SSH connection
Invalid or bad combination of options ('key_path') at parallel_ssh.pl line 41.

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
use Net::OpenSSH::Parallel;

$Net::OpenSSH::Parallel::debug = -1;

my %hosts = ( 'localhost' => { host  => "127.0.0.1",
			       user  => "user",
			       port  => "22",
			       psw   => "psw",
			       key   => "/home/user/.ssh/id_rsa", },
    );

my $maximum_workers = scalar (keys %hosts);
my $maximum_connections = 2 * $maximum_workers;
my $maximum_reconnections = 0;

my %opts = ( workers       => $maximum_workers,
	     connections   => $maximum_connections,
	     reconnections => $maximum_reconnections
    );

my $pssh = Net::OpenSSH::Parallel->new( %opts );

foreach my $label (keys %hosts) {
    $pssh->add_host( #$hosts{$label},
		     $hosts{$label}{host},
		     user              => $hosts{$label}{user},
		     port              => $hosts{$label}{port},
		     password          => $hosts{$label}{psw},
		     key_path          => $hosts{$label}{key},
	);
}

#print Dumper $pssh;
$pssh->push('*', command => 'ls');
$pssh->run;