title: Continuous "hot" deployment of an angular web app
body: <p>How to deploy a new version of an AngularJS single page web app (API based) without interrupting service ?</p>
  
  <p>We need at last :</p>
  
  <ul>
  <li>to update the sources (server and client)</li>
  <li>to migrate/update the database</li>
  <li>to relaunch the server</li>
  </ul>
  
  <p>Even with a load balancer and at last 2 rotating servers (one updating while the other is serving), I can't figure a safe way to deploy a new version without interrupting service and without losing user data.</p>
  
  <p>Imagine a user working on a complex document in our web app. We can't force reload its page during its work session...</p>
  
  <p>How to do it ?
  If not possible, how to mitigate the issue ?</p>