Rails, Docker: Host does not exist: "default"

Question

When I try to run docker-machine start default , I get Host does not exist: "default", I tried eval "$(docker-machine env default)", but still getting the same message. Where is the error ?

Answer 1

Try simply to check what machine has been created (docker-machine ls):

docker-machine ls 

Then you can pick one and try your commands with it.

If there is none, you can create one first (docker-machine create).
In the case of the OP:

docker-machine create default 

Since the error message was:

Cannot connect to the Docker daemon. Is the docker daemon running on this host?

One of the answers of "Docker command can't connect to docker daemon" should work:

sudo service docker restart