title: Can a cpu core run multiple applications concurrently on spark cluster?
body: <p>I have two questions about Apache spark.</p>
  
  <ol>
  <li><p>I built a spark standalone cluster, each worker has 4 cores, does that mean I can only have 4 applications running concurrently on a worker at most?</p></li>
  <li><p>I have a process that I want it to be running regularly, what would be the best practice? Call <code>spark-submit</code> in a cron job or just loop my code in the driver?</p></li>
  </ol>