Install docker to Redhat 7

1)   sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

2） sudo yum install docker-ce docker-ce-cli containerd.io

3)   上面2）应该会出错，告诉你container-selinux的版本不够

4） 

1Installing the Selinux from the Centos repository worked for me: 
21. Go to http://mirror.centos.org/centos/7/extras/x86_64/Packages/ 
32. Find the latest version for container-selinux i.e. container-selinux-2.21-1.el7.noarch.rpm 
43. Run the following command on your terminal: $ sudo yum install -y http://mirror.centos.org/centos/7/extras/x86_64/Packages/**Add_current_container-selinux_package_here** 
54. The command should looks like the following $ sudo yum install -y http://mirror.centos.org/centos/7/extras/x86_64/Packages/container-selinux-2.21-1.el7.noarch.rpm 

参考：

https://docs.docker.com/install/linux/docker-ce/centos/

https://stackoverflow.com/questions/45272827/docker-ce-on-rhel-requires-container-selinux-2-9/45287245