如何在多个服务器上执行命令以执行命令

Question

i have set of servers (150) for logging and a command (to get disk space). How can i execute this command for each server. Suppose if script is taking 1 min to get report of command for single server, how can i send report for all the servers for every 10 min?

 use strict;
 use warnings;
 use Net::SSH::Perl;
 use Filesys::DiskSpace;


 # i have almost more than 100 servers..
 my %hosts   = (
    'localhost' => {
                       user  => "z",
                   password  => "qumquat",

    },


     '129.221.63.205' => {
                           user  => "z",
                       password  => "aardvark",

    },
'129.221.63.205' => {
                           user  => "z",
                       password  => "aardvark",

    },  


   );


  # file system /home or /dev/sda5 
  my $dir = "/home";

  my $cmd =  "df $dir";

  foreach my $host (keys %hosts) {
          my $ssh = Net::SSH::Perl->new($host,port => 22,debug => 1,protocol => 2,1 );    

      $ssh->login($hostdata{$host}{user},$hostdata{$host}{password} );
      my ($out) = $ssh->cmd($cmd});
          print "$out\n";
   }

It has to send output of disk space for each server

Answer 1

Is there a reason this needs to be done in Perl? There is an existing tool, dsh , which provides precisely this functionality of using ssh to run a shell command on multiple hosts and report the output from each. It also has the ability, with the -c (concurrent) switch to run the command at the same time on all hosts rather than waiting for each one to complete before going on to the next, which you would need if you want to monitor 150 machines every 10 minutes, but it takes 1 minute to check each host.

To use dsh , first create a file in ~/.dsh/group/ containing a list of your servers. I'll put mine in ~/.dsh/group/test-group with the content:

galera-1
galera-2
galera-3

Then I can run the command

dsh -g test-group -c 'df -h /'

And get back the result:

galera-3: Filesystem                 Size  Used Avail Use% Mounted on
galera-3: /dev/mapper/debian-system  140G   36G   99G  27% /
galera-1: Filesystem                 Size  Used Avail Use% Mounted on
galera-1: /dev/mapper/debian-system  140G   29G  106G  22% /
galera-2: Filesystem                 Size  Used Avail Use% Mounted on
galera-2: /dev/mapper/debian-system  140G   26G  109G  20% /

(They're out-of-order because I used -c , so the command was sent to all three servers at once and the results were printed in the order the responses were received. Without -c , they would appear in the same order the servers are listed in the group file, but then it would wait for each reponse before connecting to the next server.)

But, really, with the talk of repeating this check every 10 minutes, it sounds like what you really want is a proper monitoring system such as Icinga (a high-performance fork of the better-known Nagios ), rather than just a way to run commands remotely on multiple machines (which is what dsh provides). Unfortunately, configuring an Icinga monitoring system is too involved for me to provide an example here, but I can tell you that monitoring disk space is one of the checks that are included and enabled by default when using it.

Answer 2

There is a ready-made tool called Ansible for exactly this purpose. There you can define your list of servers, group then and execute commands on all of them.