title: Guarantee that some operators will be executed on the same airflow worker
body: <p>I have a DAG which </p>
  
  <ol>
  <li>downloads a csv file from cloud storage</li>
  <li>uploads the csv file to a 3rd party via https</li>
  </ol>
  
  <p>The airflow cluster I am executing on uses <code>CeleryExecutor</code> by default, so I'm worried that at some point when I scale up the number of workers, these tasks may be executed on different workers. eg. worker A does the download, worker B tries to upload, but doesn't find the file (because it's on worker A)</p>
  
  <p>Is it possible to somehow guarantee that both the download and upload operators will be executed on the same airflow worker? </p>