title: Unit docker.service is not loaded properly observed while execute service docker start on Ubuntu
body: <p>I just successfully installed docker on ubuntu machine but I'm not able to start and it throws below error message</p>
  
  <p><strong>Command:</strong></p>
  
  <blockquote>
    <p>sudo service docker start</p>
  </blockquote>
  
  <p><strong>Error:</strong></p>
  
  <pre><code>Job for docker.socket failed. See "systemctl status docker.socket" and "journalctl -xe" for details.
  Failed to start docker.service: Unit docker.service is not loaded properly: Invalid argument.
  See system logs and 'systemctl status docker.service' for details
  </code></pre>
  
  <p>.</p>
  
  <p>System details:</p>
  
  <blockquote>
    <p>Uname -a</p>
    
    <p>Linux instance-1 4.15.0-1029-gcp #31~16.04.1-Ubuntu SMP Fri Mar 22
    13:06:42 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux</p>
    
    <p>Docker version 18.09.2, build 6247962</p>
  </blockquote>
  
  <p>Also I do see the below while check the docker info:</p>
  
  <pre><code>sudo docker info
  [sudo] password for achu:
  Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
  </code></pre>
  
  <p>I got below details if I run systemctl status docker.socket</p>
  
  <pre><code>● docker.socket - Docker Socket for the API
     Loaded: loaded (/lib/systemd/system/docker.socket; enabled; vendor preset: enabled)
     Active: failed (Result: service-start-limit-hit) since Thu 2019-05-09 03:53:13 PDT; 5h 0min ago
     Listen: /var/run/docker.sock (Stream
  </code></pre>
  
  <p>Also I just checked docker.socket file and I don't see any docker.sock in /var/run/docker.sock location.</p>
  
  <p>Any help will be appreciated.</p>