title: mount: only root can use "--types" option (effective UID is 2000)
body: <p>I tried to execute the mount command inside my debian:9 container but getting issue as follows even though running as a root use.</p>
  
  <p>container run command:</p>
  
  <pre><code>docker run --privileged --userns=host  -it --rm -u root &lt;customimage with debian:9&gt; /bin/sh
  </code></pre>
  
  <p>mount command inside the container</p>
  
  <pre><code>mkdir -p /tmp/overlay
  mount -t tmpfs tmpfs /tmp/overlay
  </code></pre>
  
  <p>exception</p>
  
  <pre><code>mount: only root can use "--types" option (effective UID is 2000)
  </code></pre>