Ubuntu18重启docker服务失败问题备忘

root@hedy:~# systemctl restart docker
Failed to restart docker.service: Unit docker.service not found.

root@hedy:~# snap services
Service         Startup  Current  Notes
docker.dockerd  enabled  active   -

root@hedy:~# docker.help
Docker snap: Docker Linux container runtime.

Due to the confinement issues on snappy, it requires some manual setup to make docker-snap works on your machine.
We'll take you through the steps needed to set up docker snap work for you on ubuntu core and ubuntu classic.

On Ubuntu classic, before installing the docker snap,
please run the following command to add the login user into docker group.
    sudo addgroup --system docker
    sudo adduser $USER docker
    newgrp docker

On Ubuntu Core 16, after installing the docker snap from store,
you need to connect the home interface as it's not auto-connected by default.
    sudo snap connect docker:home :home

Then have fun with docker in snappy.

root@hedy:~# snap restart docker
Restarted.