title: Why doesn't "service cron start" work within the Docker file?
body: <p>When I start the cron service within the running Docker container with</p>
  
  <pre><code>service cron start
  </code></pre>
  
  <p>it works. But the line</p>
  
  <pre><code>RUN service cron start
  </code></pre>
  
  <p>within the Dockerfile seems not to have an effect. Why?</p>
  
  <h2>Alternatives</h2>
  
  <p>I thought about simply changing my <code>CMD</code> to something like <code>CMD ["startup.sh"]</code> which first runs <code>service cron start</code> and then <code>run.py</code> (a Python webserver). But I want the web server not to run as root and thus <code>service cron start</code> would fail.</p>