title: Why is Config.User an empty string when I inspect a Docker container?
body: <p>I pulled and ran the Docker container <a href="https://hub.docker.com/r/jcsilva/docker-kaldi-gstreamer-server/" rel="nofollow noreferrer">jcsilva/docker-kaldi-gstreamer-server</a>:</p>
  
  <pre><code>docker pull jcsilva/docker-kaldi-gstreamer-server
  docker run -it -p 8080:80 -v /media/kaldi_models:/opt/models jcsilva/docker-kaldi-gstreamer-server:latest /bin/bash
  </code></pre>
  
  <p>I can see it running:</p>
  
  <pre><code>username@server:~$ docker ps
  CONTAINER ID        IMAGE                                          COMMAND                  CREATED             STATUS              PORTS                                                                                                     NAMES
  24f598fd5019        jcsilva/docker-kaldi-gstreamer-server:latest   "/bin/bash"              12 hours ago        Up 12 hours         0.0.0.0:8080-&gt;80/tcp     
  </code></pre>
  
  <p>When I inspect it:</p>
  
  <pre><code>username@server:~$ docker inspect 24f598fd501911f32e10884ed3f86547e05a031f0d31324badc40c5fb5ed732a &gt; inspection.json
  </code></pre>
  
  <p>I see in the <code>inspection.json</code>:</p>
  
  <pre><code>    "Config": {
          "Hostname": "24f598fd5019",
          "Domainname": "",
          "User": "",                       &lt;-- Why is User an empty string?
          "AttachStdin": true,
          "AttachStdout": true,
          "AttachStderr": true,
          "ExposedPorts": {
              "80/tcp": {}
          },
  </code></pre>
  
  <p>What could explain that Config.User is an empty string?</p>
  
  <p>I use Docker version 18.03.0-ce, build 0520e24 on Ubuntu 16.04.4 LTS (GNU/Linux 4.4.0-119-generic x86_64).</p>