#!/usr/local/bin/php
<?php
$load = sys_getloadavg();
$cpus = substr_count(file_get_contents("/proc/cpuinfo"),"processor");

$usage = trim(shell_exec("sudo vmstat 1 2|tail -1|awk '{print $15}'"));
$usage = 100 - $usage;

$msg = "System load: ${load[0]} ($cpus CPUs), CPU usage: ${usage}%";

if ($load[0] > ($cpus * 1.5) || ($load[1] >= ($cpus - 2)) || $usage > 70) {
        echo "CRITICAL: $msg";
        exit(2);
} else {
        echo "OK: $msg";
        exit(0);
}