Ubuntu 16.04 - > ERROR: Couldn't connect to Docker daemon - you might need to run `docker-machine start default`

Question

I am getting error on ubuntu 16.04

\"ERROR: Couldn\'t connect to Docker daemon - you might need to run docker- machine start default. \"

Answer 1

After installing can execute command to have access to docker functionality without sudo. In my sitation, with same errors all is resolved after :

$ sudo usermod -aG docker ${USER}
$ su - ${USER}
$ id -n
$ sudo usermod -aG docker username

and can restart docker after that:

systemctl restart docker