$ uname -r
3.10.0-229.el7.x86_64

$ sudo yum update

$ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/7/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF

$ sudo yum install docker-engine

$ sudo systemctl enable docker.service

$ sudo systemctl start docker

$ sudo docker run --rm hello-world

$ sudo yum update

$ curl -fsSL https://get.docker.com/ | sh

$ sudo systemctl enable docker.service

$ sudo systemctl start docker

$ sudo docker run --rm hello-world