title: docker not starting and failing with error , Failed to start docker.service: Unit not found
body: <p>When I am trying to start docker using the command:</p>
  <pre><code>sudo systemctl start docker 
  </code></pre>
  <p>I am getting below error</p>
  <pre><code>Failed to start docker.service: Unit not found.
  </code></pre>
  <p>I tried finding some suggestions over the web to resolve this issue and followed that but it didn't solve the issue.</p>
  <blockquote>
  <p><a href="https://stackoverflow.com/questions/42217526/cannot-start-docker-daemon-in-centos7">Cannot start docker daemon in CentOS7</a></p>
  </blockquote>
  <p>This is my docker.socket file [which is just a copy-paste of one of the answer]</p>
  <pre><code>[Unit]
  Description=Docker Socket for the API
  PartOf=docker.service
  
  [Socket]
  ListenStream=/var/run/docker.sock
  SocketMode=0660
  SocketUser=root
  SocketGroup=docker
  
  [Install]
  WantedBy=sockets.target
  </code></pre>
  <p>This is the error I am getting error while starting docker.socket</p>
  <pre><code>sudo systemctl start docker.socket
  
  See &quot;systemctl status docker.socket&quot; and &quot;journalctl -xe&quot; for details.
  </code></pre>
  <p>output of &quot;systemctl status docker.socket&quot;</p>
  <pre><code>systemctl status docker.socket
  
  systemd[1]: Socket service docker.service not loaded, refusing.
  systemd[1]: Failed to listen on Docker Socket for the API.
  </code></pre>
  <p>docker version details</p>
  <pre><code>Client: Docker Engine - Community
   Version:           19.03.2
   API version:       1.40
   Go version:        go1.12.8
   Git commit:        6a30dfca03
   Built:             Thu Aug 29 05:26:30 2019
   OS/Arch:           linux/amd64
   Experimental:      false
  Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
  </code></pre>
  <p>To me, it looks like that docker.service is an issue. Could you please suggest how I can resolve it.</p>