First, add the GPG key for the official Docker repository to the system:
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
Add the Docker repository to APT sources:
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
Next, update the package database with the Docker packages from the newly added repo:
sudo apt-get update
Make sure you are about to install from the Docker repo instead of the default Ubuntu 16.04 repo:
apt-cache policy docker-ce
Now Install
sudo apt-get install -y docker-ce
Check Status
sudo systemctl status docker
Output
● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Active: active (running) since Sun 2016-05-01 06:53:52 CDT; 1 weeks 3 days ago
Docs: https://docs.docker.com
Main PID: 749 (docker)