title: How can an application running in a docker container detect that the docker host rebooted?
body: <p>I have an application (Django) running in a docker container on a cloud provider. For various reasons it would be useful for me to know when the host itself rebooted, and to save this event somewhere e.g. a database. Obviously it's easy to detect when the application itself starts, but this could have been caused by something other than host reboot.
  I could in theory catch SIGTERM but again this doesn't necessarily mean a host reboot.</p>
  
  <p>As usual while writing this question I've realised that I could just call <code>uptime</code> and pass through <code>/proc/uptime</code> if necessary, but is this the best way?</p>