code: public function updateSentinels()
      {
          SENTINEL_QUERY: {
              $sentinel = $this->getSentinelConnection();
  
              try {
                  $payload = $sentinel->executeCommand(
                      RawCommand::create('SENTINEL', 'sentinels', $this->service)
                  );
  
                  $this->sentinels = array();
                  // NOTE: sentinel server does not return itself, so we add it back.
                  $this->sentinels[] = $sentinel->getParameters()->toArray();
  
                  foreach ($payload as $sentinel) {
                      $this->sentinels[] = array(
                          'host' => $sentinel[3],
                          'port' => $sentinel[5],
                          'role' => 'sentinel',
                      );
                  }
              } catch (ConnectionException $exception) {
                  $this->sentinelConnection = null;
  
                  goto SENTINEL_QUERY;
              }
          }
      }
docs: Fetches an updated list of sentinels from a sentinel.