title: how to change root dir of docker on ubuntu 18.04 LTS? (docker change location of volumes)
body: <p>I installed ubuntu 18.04 LTS and checked a setting for docker (17.06.2-ce) to install at the same time.</p>
  
  <p>I tested by starting the hello-world (<code>sudo docker run hello-world</code>) :</p>
  
  <p>[...]
  Hello from Docker!
  This message shows that your installation appears to be working correctly.
  [...]</p>
  
  <p>I mounted a software raid on the folder named <code>/raid</code>, and make a folder <code>/docker-data</code> in it.</p>
  
  <p>I try to change the root dir of my docker to put it in <code>/raid/docker-data/</code> by following the few tutorials on the network... in vain.</p>
  
  <p><a href="https://stackoverflow.com/questions/26711103/docker-changing-var-lib-docker-aufs-diff-location">these solutions don't work either</a> :</p>
  
  <ul>
  <li><code>/etc/default/docker</code> : I can't find this</li>
  <li>As in the 2nd solution : docker can't find his folder.</li>
  </ul>
  
  <p>Docker Root Dir: /var/snap/docker/common/var-lib-docker</p>
  
  <p>Has anyone managed to do this feat in recent months?</p>
  
  <p>(this is my 3rd installation of ubuntu and I just broke it...)</p>
  
  <hr>
  
  <p>Apparently on Ubuntu 18.04 LTS, docker 17.06.2-it needs to work with snap, I'm going to dig this way. I will try to return answer later...</p>