Greetings Monks! I am trying to write a script which will monitor available memory on a cisco router. The scrip works without issues when ran on a single node. However, when i try to add additional switches or routers the script fails frequently. If a script fails to log into any of the routers or switches it fails all together. I am using eval to check my ssh connection before running any commands and it helped a little. However, if i add more than 3-4 switches, the script fails pretty consistently. It could have something do do with Net::SSH2 module as this is my first time using it, but i am not 100% sure. Any help would be greatly appreciate it!

#! /usr/bin/perl

use Net::SSH2;
use warnings;
use strict;
use Data::Dumper;
use Net::Syslog;



my $user = "user";
my $password = 'password';
my $secret = 'secret';        ### enable password 


my @hosts=qw/switch1 switch2 switch3 switch4 switch5 switch6/; 

my (%deviceHash, $total, $total_unicast,$total_ipv4nonvrf,$total_ipv4v
+rf, $total_multicast, $total_mpls, $host, $connect, $s, $ssh);

my $array_count= scalar @hosts;



foreach (@hosts){
&connect;
}

my $hash_count = keys %deviceHash;
my $i=0;

print "The number of keys in the hash $hash_count\n";

if(($array_count != $hash_count) && ($i<=2)){
    print "went into conditional statement\n";
    print "the kyes $_\n" for keys %deviceHash;
    foreach my $connection(@hosts){
    if (exists $deviceHash{$connection}){
        print "the $connection host exists\n";
        }
        else{
            print "the $connection doesn't exist";
            &connect($connection);
            }
    }
$i++
}


sub connect {

$host=$_;
$ssh = Net::SSH2->new();

my $retry_count = 0;
my $max_retry_count =5;

    while($retry_count <= $max_retry_count){
        my $rc = eval { $ssh->connect($host); }; 
        last if defined $rc;
        $retry_count++;
        sleep 2;
    }

    if ($@) {   
        &mail2 ($host);
        print "output on $host $@\n";
        next;
   }
   
if(!$ssh->auth_password($user,$password)){
        print("Authentication Failed");
        exit(1);
}
my $channel = $ssh->channel();

$channel->blocking(0);
$channel->shell();
$channel->write("enable\n");
$channel->write("$secret\n");     ### enable password from input strin
+g3
$channel->write("term len 0\n");
print $channel "sh mls cef sum\n";

  while (<$channel>) {
    unless($_ =~ /routes/){
    next;
    }
    if ($_ =~ /Total routes/){
    $total = (split(/:/, $_))[1];
    $total =~ s/^\s+//;
    $total =~ s/\s+$//;
    $deviceHash{$host}{"Total"} = $total;
    }
    elsif($_ =~ /IPv4 unicast routes/){
    $total_unicast = (split(/:/, $_))[1];
    $total_unicast =~ s/^\s+//;
    $total_unicast =~ s/\s+$//;
    $deviceHash{$host}{"Total_Unicast"} = $total_unicast;
    }
    elsif($_ =~ /IPv4 non-vrf routes/){
    $total_ipv4nonvrf = (split(/:/, $_))[1];
    $total_ipv4nonvrf =~ s/^\s+//;
    $total_ipv4nonvrf =~ s/\s+$//;
    $deviceHash{$host}{"Total_IPV4_NONVRF"} = $total_ipv4nonvrf;
    }
    elsif($_ =~ /IPv4 vrf routes/){
    $total_ipv4vrf = (split(/:/, $_))[1];
    $total_ipv4vrf =~ s/^\s+//;
    $total_ipv4vrf =~ s/\s+$//;
    $deviceHash{$host}{"Total_IPV4_VRF"} = $total_ipv4vrf;
    }
    elsif($_ =~ /IPv4 Multicast routes/){
    $total_multicast = (split(/:/, $_))[1];
    $total_multicast =~ s/^\s+//;
    $total_multicast =~ s/\s+$//;
    $deviceHash{$host}{"Total_IPV4_MULTICAST"} = $total_multicast;
    }
    elsif($_ =~ /MPLS routes/){
    $total_mpls = (split(/:/, $_))[1];
    $total_mpls  =~ s/^\s+//;
    $total_mpls  =~ s/\s+$//;
    $deviceHash{$host}{"Total_IPV4_MULTICAST"} = $total_mpls;
    }
}
 # exit the routine
$channel->write('exit');
 # Close the connection
$ssh->disconnect();
#sleep (1);

}

foreach my $key (keys %deviceHash){
if ($deviceHash{$key}{"Total"} >= 100000){
$s = new Net::Syslog();
my $memory = $deviceHash{$key}{"Total"};
$s->send("TCAM memory is being exhausted on $key, the current memory i
+s $memory",Name=>'tcam-test',Facility=>'local7',Priority=>'info',Sysl
+ogHost=>'192.168.0.1');
#print "the TCAM memory is being exhausted on $key, the current memory
+ is $memory \n";

   }
}




sub mail2 {

my $node=shift;
my @to=qw/host.email.com/;

    open(MAIL, "|/usr/sbin/sendmail -t");

    ## Mail Header
    print MAIL "To: @to\n";
    print MAIL "From: root\n";
    print MAIL "Subject: The tcam monitoring script was not able to lo
+g into  $node\n";

    ##Mail Body
    print MAIL "The tcam monitoring script was not able to log into  $
+node\n";
    print MAIL "If the problem repeats itself please investigate as so
+on as possible\n";
    close(MAIL);
}
[download]

The output of the command that is being assigned to the hash goes something like this: Total routes: 94000 IPv4 unicast routes: 94000 IPv4 non-vrf routes: 130 IPv4 vrf routes: 95000 IPv4 Multicast routes: 65 MPLS routes: 560 IPv6 unicast routes: 3 IPv6 non-vrf routes: 2 IPv6 vrf routes: 0 IPv6 multicast routes: 5 EoM routes: 1

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