title: Start the app through the puppet with params based on the fact
body: <p>I have a part in <em>init.pp</em>, that starts my app:</p>
  
  <pre><code>systemd::service {'app':
      user =&gt; 'java',
      exec =&gt; "${java_home}/bin/java \
      -server \
      '-XX:OnOutOfMemoryError=\\'kill -9 %%p\\'' \
      -Dmw.config=/etc/app/app.config \
      -cp /usr/share/app/app.jar ru.app.main.Main app",
  }
  </code></pre>
  
  <p>The newer version of the <em>app.jar</em> starts differently. There's a way, stop the puppet on the nodes, deregister the node from the consul, start the puppet with the new <em>init.pp</em>, and put that node back to the consul. But that just doesn't feel right.</p>
  
  <p>Is there a way to put some <strong>"if"</strong> in there so I'd be able to make smooth transitions back and forth depending on my app's version or any other field? </p>