docker daemon

ubuntu@ip-172-31-55-180:~$ eval "$(docker-machine env default)"
docker-machine: command not found
ubuntu@ip-172-31-55-180:~$ docker version
Client:
 Version:      1.12.1
 API version:  1.24
 Go version:   go1.6.3
 Git commit:   23cf638
 Built:        Thu Aug 18 05:22:43 2016
 OS/Arch:      linux/amd64
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
ubuntu@ip-172-31-55-180:~$ docker-machine ssh default
docker-machine: command not found
ubuntu@ip-172-31-55-180:~$ docker run hello-world
docker: Cannot connect to the Docker daemon. Is the docker daemon running on this host?.
See 'docker run --help'.