[root@deployer ~]# sudo systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/docker.service.d
           └─kolla.conf
   Active: failed (Result: exit-code) since Tue 2016-08-16 22:22:06 EDT; 10min ago
     Docs: https://docs.docker.com
  Process: 2685 ExecStart=/usr/bin/dockerd --storage-driver btrfs (code=exited, status=1/FAILURE)
 Main PID: 2685 (code=exited, status=1/FAILURE)

Aug 16 22:22:05 deployer.local systemd[1]: Starting Docker Application Container Engine...
Aug 16 22:22:05 deployer.local dockerd[2685]: time="2016-08-16T22:22:05.754409095-04:00" level=info msg="libcontainerd: new containerd process, pid: 2691"
Aug 16 22:22:06 deployer.local dockerd[2685]: time="2016-08-16T22:22:06.759772915-04:00" level=fatal msg="Error starting daemon: error initializing gra...system?)"
Aug 16 22:22:06 deployer.local systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
Aug 16 22:22:06 deployer.local systemd[1]: Failed to start Docker Application Container Engine.
Aug 16 22:22:06 deployer.local systemd[1]: Unit docker.service entered failed state.
Aug 16 22:22:06 deployer.local systemd[1]: docker.service failed.
Hint: Some lines were ellipsized, use -l to show in full.