1.文档
https://docs.docker.com/engine/install/centos/
https://docs.docker.com/engine/install/linux-postinstall/
2.卸载旧版
yum remove -y docker \
docker-ce-cli \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-selinux \
docker-engine-selinux \
docker-engine \
container*;