echo "安装 docker 所需环境"

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

echo "添加 repo（可能网络会很慢，有时候会报：Timeout，所以要多试几次）"

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

yum makecache fast

echo "开始安装 docker"

yum install -y docker-ce

echo "启动 Docker"

systemctl start docker.service

echo "安装结束"

echo "运行 hello world 镜像"

docker run hello-world