If you run docker on a Mac you can get the following error:
2018/05/15 22:17:52 Post http:///var/run/docker.sock/v1.15/containers/create: dial unix /var/run/docker.sock: no such file or directory
This indicates that the Docker service isn’t running.
You can “fix” this by simply running docker manually:
/Applications/Docker.app/Contents/MacOS/Docker