title: Unable to start Docker service with error "Failed to start docker.service: Unit not found."
body: <p>I have installed Docker with <code>yum install docker</code>:</p>
  
  <pre><code>$ uname -a
  Linux caspgval4 3.10.0-229.20.1.el7.x86_64 #1 SMP Wed Nov 4 10:08:36 CST 2015 x86_64 x86_64 x86_64 GNU/Linux
  
  $ docker --version
  Docker version 1.12.6, build 3a094bd/1.12.6
  
  $ docker info
  Cannot connect to the Docker daemon. Is the docker daemon running on this host?
  
  $ sudo systemctl status docker
  ● docker.service - Docker Application Container Engine
     Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
     Active: inactive (dead)
       Docs: http://docs.docker.com
  </code></pre>
  
  <p>I am trying to install and run Docker, but it is giving an error as below:</p>
  
  <pre><code>$ sudo service docker start
  Redirecting to /bin/systemctl start  docker.service
  Failed to start docker.service: Unit not found.
  </code></pre>
  
  <p>How do I resolve this issue? I tried the following commands, but no luck:</p>
  
  <pre><code>$ sudo systemctl start docker
  Failed to start docker.service: Unit not found.
  </code></pre>
  
  <p>Extra information:</p>
  
  <pre><code>$ journalctl -u docker
  No journal files were found.
  -- No entries --
  
  $ cat /usr/lib/systemd/system/docker.service
  [Unit]
  Description=Docker Application Container Engine
  Documentation=http://docs.docker.com
  After=network.target
  Wants=docker-storage-setup.service
  Requires=rhel-push-plugin.socket
  Requires=docker-cleanup.timer
  
  [Service]
  Type=notify
  NotifyAccess=all
  EnvironmentFile=-/etc/sysconfig/docker
  EnvironmentFile=-/etc/sysconfig/docker-storage
  EnvironmentFile=-/etc/sysconfig/docker-network
  Environment=GOTRACEBACK=crash
  Environment=DOCKER_HTTP_HOST_COMPAT=1
  Environment=PATH=/usr/libexec/docker:/usr/bin:/usr/sbin
  ExecStart=/usr/bin/dockerd-current \
            --add-runtime docker-runc=/usr/libexec/docker/docker-runc-current \
            --default-runtime=docker-runc \
            --authorization-plugin=rhel-push-plugin \
            --exec-opt native.cgroupdriver=systemd \
            --userland-proxy-path=/usr/libexec/docker/docker-proxy-current \
            $OPTIONS \
            $DOCKER_STORAGE_OPTIONS \
            $DOCKER_NETWORK_OPTIONS \
            $ADD_REGISTRY \
            $BLOCK_REGISTRY \
            $INSECURE_REGISTRY
  ExecReload=/bin/kill -s HUP $MAINPID
  LimitNOFILE=1048576
  LimitNPROC=1048576
  LimitCORE=infinity
  TimeoutStartSec=0
  Restart=on-abnormal
  MountFlags=slave
  
  [Install]
  WantedBy=multi-user.target
  </code></pre>
  
  <p>I tried the following:</p>
  
  <pre><code>$ sudo systemctl daemon-reload
  $ sudo systemctl start docker
  Failed to start docker.service: Unit not found.
  $ sudo journalctl -u docker
  -- No entries --
  </code></pre>
  
  <p>More debug information:</p>
  
  <pre><code>$ sudo systemctl status network.target
  ● network.target - Network
     Loaded: loaded (/usr/lib/systemd/system/network.target; static; vendor preset: disabled)
     Active: active since Mon 2017-01-23 02:54:39 PST; 2 months 29 days ago
       Docs: man:systemd.special(7)
             http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget
  
  Jan 23 02:54:39 mymachine systemd[1]: Starting Network.
  Jan 23 02:54:39 mymachine systemd[1]: Reached target Network.
  
  $ sudo systemctl status docker-storage-setup.service
  ● docker-storage-setup.service - Docker Storage Setup
     Loaded: loaded (/usr/lib/systemd/system/docker-storage-setup.service; disabled; vendor preset: disabled)
     Active: inactive (dead)
  
  $ sudo systemctl status rhel-push-plugin.socket
  Unit rhel-push-plugin.socket could not be found.
  
  $ sudo systemctl status docker-cleanup.timer
  ● docker-cleanup.timer - Run docker-cleanup every hour
     Loaded: loaded (/usr/lib/systemd/system/docker-cleanup.timer; disabled; vendor preset: disabled)
     Active: inactive (dead)
  </code></pre>