public function removeAllClusters($is_all = false)
{
$clusters = $this->getClusters();
foreach ($clusters['list'] as $cluster) {
// Determine if the cluster should be deleted
if (!$is_all && substr(strtolower($cluster), 0, strlen($this->clusterPrefix)) != $this->clusterPrefix) {
continue;
}
$this->removeCluster($cluster);
}
}