pick_mini_node

#!/usr/bin/perl -w

# The MIT License
#
# Copyright (c) 2014 Goo Jun <gjun@umich.edu> Adrian Tan <atks@umich.edu>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# This was modified from Goo's pick_mininode script
# 
# 1. modified to take in the number of seconds to randomize for sleep
#    time. 0 seconds is the default.

use strict;
use warnings;

sleep(int(rand()*(@ARGV ? $ARGV[0]: 0)));

my @cnt = (0, 0, 0, 0);
my $min = 10000;
my $pick = 0;

my $host = `hostname`;

if ($host =~ /(fantasia|wonderland|snowwhite|dumbo)/)
{
    die "Not a mini cluster\n";
}

open(IN, "mosps -eu |tail -n +2|");
while(<IN>)
{
    my ($user, $pid, $node) = split(/\s+/);
    
    next if $node eq "here";
    $cnt[$node-10]++;
}
close IN;

my @tie = ();
for(my $i=0;$i<4;++$i)
{
    if ($cnt[$i]<=$min)
    {
        $min = $cnt[$i];
        $pick = $i;
    }
}

for(my $i=0;$i<4;++$i)
{
    if ($cnt[$i] == $min)
    {
        push(@tie, $i);
    }
}

$pick = $tie[int(rand(@tie))];

print $pick+10;