/**
	 * @param  $groupname
	 * @param  $description
	 * @return null|OpenStackNovaSecurityGroup
	 */
	function createSecurityGroup( $groupname, $description ) {
		$response = $this->novaConnection->create_security_group( $groupname, $description );
		if ( ! $response->isOK() ) {
			return null;
		}
		$securityGroup = new OpenStackNovaSecurityGroup( $response->body->securityGroupSet->item );
		$groupname = $securityGroup->getGroupName();
		$this->securityGroups["$groupname"] = $securityGroup;

		return $securityGroup;
	}
 /**
  * @return array
  */
 function getSecurityGroups()
 {
     $ret = $this->restCall('compute', '/os-security-groups', 'GET');
     $groups = array();
     $securityGroups = self::_get_property($ret['body'], 'security_groups');
     if (!$securityGroups) {
         return $groups;
     }
     foreach ($securityGroups as $securityGroup) {
         $securityGroupObj = new OpenStackNovaSecurityGroup($securityGroup);
         $groupid = $securityGroupObj->getGroupId();
         $groups[$groupid] = $securityGroupObj;
     }
     return $groups;
 }