centos7 use Ali cloud repo installation docker

1. Install the necessary number of system tools

sudo yum install -y yum-utils device-mapper-persistent-data lvm2

2. Add Ali cloud software source

sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

3. Installation Docker-CE

sudo yum -y install docker-ce