Please notice that while Docker-CE is not supported for RHEL, if you still want to install it the RedHat 'extras' channel is as of version 17.06 a prerequisite that provides the container-selinux package. @NBardelot
# get docker ce
sudo yum install -y yum-utils
sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
sudo yum makecache fast
# install container-selinux
sudo yum install https://www.rpmfind.net/linux/centos/7.4.1708/extras/x86_64/Packages/container-selinux-2.21-1.el7.noarch.rpm
# install docker
sudo yum -y install docker-ce
# start
sudo systemctl start docker
# configure docker to start on boot
sudo systemctl enable docker