title: failed to start daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid
body: <p>I start docker</p>
  <pre><code>sudo service docker start
  </code></pre>
  <p>then I try to run dockerd</p>
  <pre><code>sudo dockerd
  </code></pre>
  <p>it shows the following error:</p>
  <blockquote>
  <p>INFO[2021-11-21T19:25:52.804962676+05:30] Starting up<br />
  failed to start daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid</p>
  </blockquote>