SSH connection to 100 routers

vasanth.easyrider has asked for the wisdom of the Perl Monks concerning the following question:

Hi Perl monks

I have a requirement where i need to connect to 900 routers and execute few commands and capture the output. I am using Net::OpenSSH module for fulfilling my requirement. But we have ssh key authentication issue that is causing a problem for me. I cant manually connect to 900 servers to establish the SSH key. Is there a method for me to tackle it in script. The script given below is being used to connect to 1 router and execute the command

#!/usr/bin/perl
use strict;
use warnings;

use Net::OpenSSH;
my ($ssh,$password);
my $host = "10.0.0.183";
my $user_name = q(username);
$password = q(My_Password);
$ssh = Net::OpenSSH->new($host, user => $user_name, password => $passw
+ord);

my $output = $ssh->system("show isis neighbors") or
    die "remote command failed: " . $ssh->error;
print "output is = $output\n";
[download]

Comment on SSH connection to 100 routers Download Code

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Re: SSH connection to 100 routers by thanos1983 (Parson) on Feb 23, 2018 at 11:23 UTC
Hello vasanth.easyrider, I think you should be looking for Net::OpenSSH::Parallel. Alternatively you can create a `foreach` loop to connect to all nodes. I would not use password authentication if I was you I would use ssh key authentication (more secure). Sample of code for Net::OpenSSH::Parallel can be found here Re: multiple machines disk space alert. Sample of code using `foreach` loop and Net::OpenSSH can be found here Re: Simple SSH based chat client. Hope this helps. BR / Thanos Seeking for Perl wisdom...on the process of learning...not there...yet!	[reply] [d/l] [select]
Re: SSH connection to 100 routers by karlgoethebier (Abbot) on Feb 24, 2018 at 11:26 UTC
"...I cant manually connect to 900 servers to establish the SSH key..." Probably you can delegate this to a script. What about something like this: `sshpass -f secrets.file ssh-copy-id user@host`? I don't remember the exact syntax. Please see sshpass and ssh-copy-id for details. Best regards, Karl ŤThe Crux of the Biscuit is the Apostropheť `perl -MCrypt::CBC -E 'say Crypt::CBC->new(-key=>'kgb',-cipher=>"Blowfish")->decrypt_hex($ENV{KARL});'`Help	[reply] [d/l] [select]
Re: SSH connection to 100 routers by eighty-one (Curate) on Feb 26, 2018 at 15:06 UTC
There is a tool called rancid that handles this via expect. The expect man page is actually pretty good and should give you a decent overview of what it can do. I think the rancid devs use the shell version of expect via a bash script (I haven't looked in quite a while so I'm not sure). CPAN has a few Expect modules. Rex::Helper::SSH2::Expect looks interesting but I have no experience with it.	[reply]
Re: SSH connection to 100 routers by Anonymous Monk on Feb 26, 2018 at 14:44 UTC
Also do not overlook the capabilities of existing infrastructure-maintenance tools such as Nagios.	[reply]

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