sudo apt-get install apt-transport-https
sudo apt-key adv --keyserver hkp://pgp.mit.edu:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
sudo bash -c "echo deb https://apt.dockerproject.org/repo ubuntu-trusty main > /etc/apt/sources.list.d/docker.list"
sudo apt-get -y update
sudo apt-get -y install docker-engine
注：对于已安装的低版本docker不用手动卸载，直接覆盖安装即可
