CentOS安装 Docker（在线）

（1）查看现有的Docker环境

yum list installed | grep docker

（2）卸载现有的Docker环境

yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-engine

（3）设置本地源

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

（4）安装Docker

yum install docker-ce -y

（5）配置镜像加速

mkdir -p /etc/docker

tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://e3r7iyl5.mirror.aliyuncs.com"]
}
EOF

sudo systemctl daemon-reload

（6）启动Docker

systemctl restart docker