Ganglia alert on trend

gistfile1.aw

<?php

$rrd_file = "/var/lib/ganglia/rrds/Test Cluster/localhost.localdomain/load_one.rrd";


$command = "/usr/bin/rrdtool xport --start '-600s' --end '-30s' ";
$command .= " --daemon unix:/tmp/rrdcached.limited.sock ";
$command .= "DEF:'sum'='" . $rrd_file . ":sum':AVERAGE XPORT:sum:metric_value VDEF:D2=sum,LSLSLOPE ";
$command .= "VDEF:H2=sum,LSLINT CDEF:avg2=sum,POP,D2,COUNT,*,H2,+ XPORT:avg2:trend";

// Read in the XML
$fp = popen($command,"r");
$string = "";
while (!feof($fp)) {
  $buffer = fgets($fp, 4096);
  $string .= $buffer;
}
// Parse it
$xml = simplexml_load_string($string);

foreach ( $xml->data->row as $key => $objects ) {
    $values = get_object_vars($objects);
    $percent_diff = abs(100.0 * ( 1 - ( $values['v'][0] / $values['v'][1] )));
    print $percent_diff . "\n";
}

?>