code: public void start() throws Exception {
      // Disable HDFS client caching to avoid file system close() affecting other clients
      System.setProperty("fs.hdfs.impl.disable.cache", "true");
  
      resetClientPools();
  
      setupTest();
      startMasters();
      startWorkers();
      startProxy();
  
      // Reset contexts so that they pick up the updated configuration.
      reset();
    }
docs: Starts both master and a worker using the configurations in test conf respectively.