Práctica: SSH ping paralelo

El siguiente programa comprueba si el servicio SSH esta operativo en un servidor:

pp2@europa:~/src/perl/perltesting$ cat -n sshping.pl
 1  #!/usr/bin/perl
 2
 3  use warnings;
 4  use strict;
 5  use Socket;
 6  my ($remote,$port, $iaddr, $paddr, $proto, $line);
 7
 8  $remote  = $ARGV[0] || die "usage: $0 hostname";
 9  $port    = 22 ;  # the SSH port
10  $iaddr   = inet_aton($remote) || die "no such host: $remote";
11  $paddr   = sockaddr_in($port, $iaddr);
12  $proto   = getprotobyname('tcp');
13
14  socket(SOCK, PF_INET, SOCK_STREAM, $proto) || die "socket() failed: $!";
15  print "Connecting to port 22...\n";
16  connect(SOCK, $paddr) || die "connect() failed: $!";
17  print "Connected.\n";
18  $line = <SOCK>;
19  print $line;
20  exit 0 if $line =~ /SSH/;
21  exit 1;
22  __END__
23
24  =head1 NAME
25  Remote host back online test
26
27  =head1 WHERE
28
29  Question: I<Remote host back online test> at PerlMonks.
30  L<http://www.perlmonks.org/?node_id=653059>
31
32  =head1 HELP
33
34  If you want to test whether the SSH service on the remote host is ready to
35  accept logins you can try connecting to TCP port 22 on the remote host and see
36  if you can read the SSH banner from it. I adapted this example from the perlipc
37  documentation:
38
39  With the SSH server on my box running:
40
41    $ perl sshping.pl localhost; echo $?
42    Connecting to port 22...
43    Connected.
44    SSH-1.99-OpenSSH_x.xx Debian-xxx
45    0
46
47  If I stop the SSH server on my box:
48
49    $ perl sshping.pl localhost; echo $?
50    Connecting to port 22...
51    connect() failed: Connection refused at sshping.pl line 14.
52    111
53
54  You might want to have the perl script loop (with a sleep for a few seconds)
55  and retry the connect, or you could do that in an external bash script by
56  checking the exit code...
57
58    $ if perl sshping.pl localhost; then echo up; else echo down; fi
59    Connecting to port 22...
60    connect() failed: Connection refused at sshping.pl line 14.
61    down
62
63  =head1 AUTHOR
64
65  quester
66  L<http://www.perlmonks.org/?node_id=576594>

Escriba una versión paralela del programa anterior que determina que subconjunto de máquinas tiene sus servicios SSH operativos.

Véase

• La documentación del módulo Socket
• La pregunta Remote host back online test en PerlMonks:

  Remote host back online test

• El proyecto net-parscp puede darle ideas sobre como hacer la paralelización