thufir@doge:~$
thufir@doge:~$ sudo apt install docker
Reading package lists... Done
Building dependency tree
Reading state information... Done
docker is already the newest version (1.5-1).
0 upgraded, 0 newly installed, 0 to remove and 230 not upgraded.
thufir@doge:~$
thufir@doge:~$ sudo systemctl status docker
Unit docker.service could not be found.
thufir@doge:~$
thufir@doge:~$ sudo service docker start
Failed to start docker.service: Unit docker.service not found.
thufir@doge:~$
thufir@doge:~$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=17.04
DISTRIB_CODENAME=zesty
DISTRIB_DESCRIPTION="Ubuntu 17.04"
thufir@doge:~$

user@host:~$ apt-cache search docker | grep '^docker - '

docker - System tray for KDE3/GNOME2 docklet applications

sudo apt-get update

sudo apt-get install
    apt-transport-https
    ca-certificates
    curl
    software-properties-common

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

sudo add-apt-repository
    "deb [arch=amd64] https://download.docker.com/linux/ubuntu
    $(lsb_release -cs)
    stable"

sudo apt-get update

sudo apt-get install docker-ce

sudo docker run hello-world