code: private function _initLoggerCascade($configFile, $loggerName)
      {
          $err = '';
          try {
              $fs = $this->_obm->get(Filesystem::class);
              if ($fs->isAbsolutePath($configFile)) {
                  $fileName = $configFile;
              } else {
                  $fileName = BP . '/' . $configFile;
              }
              $realPath = realpath($fileName);
              if ($realPath) {
                  Cascade::fileConfig($realPath);
                  $this->_logger = Cascade::getLogger($loggerName);
              } else {
                  $err = "Cannot open logging configuration file '$fileName'. Default Magento logger is used.";
              }
          } catch (\Exception $e) {
              $err = $e->getMessage();
          } finally {
              if (is_null($this->_logger)) {
                  $this->_logger = $this->_obm->get(\Magento\Framework\Logger\Monolog::class);
                  $this->warning($err);
              }
          }
      }
docs: Configure Cascaded Monolog logger and use it.
  
  @param        $configFile
  @param string $loggerName