title: Running periodic Dataflow job
body: <p>I have to join data from Google Datastore and Google BigTable to produce some report. I need to execute that operation every minute. Is it possible to accomplish with Google Cloud Dataflow (assuming the processing itself should not take long time and/or can be split in independent parallel jobs)?</p>
  
  <ol>
  <li><p>Should I have endless loop inside the "main" creating and executing the same pipeline again and again?</p></li>
  <li><p>If most of time in such scenario is taken by bringing up the VMs, is it possible to instruct the Dataflow to use customer VMs instead?</p></li>
  </ol>
  
  <p>Thanks,</p>