添加docker-ce的yum源
实际上，添加的这个yum源仍然是el7的
yum install -y yum-utils
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
安装依赖包：
yum install https://download.docker.com/linux/fedora/30/x86_64/stable/Packages/containerd.io-1.2.6-3.3.fc30.x86_64.rpm
Install Docker Engine
安装docker-ce
yum install docker-ce -y
安装docker-ce报错:
file /usr/share/man/man1/docker-volume.1.gz from install of docker-ce-cli-1:19.03.8-3.el7.x86_64 conflicts with file from package podman-manpages-1.4.2-5.module_el8.1.0+237+63e26edc.noarch
解决方法：
yum remove podman-manpages -y
然后重新安装docker-ce即可