/**
* determine best host candidate prior to deploying a lab
*
* @return int|bool host id | FALSE on error
*/
function ace_db_get_best_host()
{
$host_table = ace_db_get_active_host_table();
$vcpu_per_thread = 4;
$lab['vcpu'] = 6;
$lab['memory'] = 5.5;
$lab['storage'] = 42;
$winning_host = NULL;
#create a shortlist of viable hosts
$host_shortlist = array();
foreach ($host_table as $host) {
# number of labs this host can support
$host_max_labs_by_vcpu = intval($host['threads'] * $vcpu_per_thread / $lab['vcpu']);
$host_max_labs_by_memory = intval($host['memory'] / $lab['memory']);
$host_max_labs_by_storage = intval($host['storage'] / $lab['storage']);
$host_max_labs = min($host_max_labs_by_vcpu, $host_max_labs_by_memory, $host_max_labs_by_storage);
# number of labs currently assigned to this host
$lab_table = ace_host_get_lab_table($host['id']);
//if ($lab_table === FALSE) {
if (!is_array($lab_table)) {
$use_percentage = 0;
$host_shortlist[] = array('id' => $host['id'], 'percentage' => $use_percentage);
} else {
$host_lab_count = count($lab_table);
# usage as percentage
if ($host_lab_count < $host_max_labs) {
$use_percentage = intval(ceil($host_lab_count / $host_max_labs * 100));
$host_shortlist[] = array('id' => $host['id'], 'percentage' => $use_percentage);
} else {
$use_percentage = 100;
$host_shortlist[] = array('id' => $host['id'], 'percentage' => $use_percentage);
}
}
}
# apply algorithm to determine host with lowest use_percentage
if (count($host_shortlist) > 0) {
$lowest_percentage = 100;
foreach ($host_shortlist as $host) {
if ($host['percentage'] < $lowest_percentage) {
$lowest_percentage = $host['percentage'];
$best_host_id = intval($host['id']);
}
}
if ($lowest_percentage == 100) {
$best_host_id = FALSE;
}
} else {
$best_host_id = FALSE;
}
return !empty($best_host_id) ? $best_host_id : FALSE;
}
/**
* returns a table of active known virtualization hosts
*
* @api
*
* @return array|bool active host table | FALSE on error
*/
function ace_get_active_hosts()
{
return ace_db_get_active_host_table();
}
