1. 移除以前docker相關包

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

3. 設置倉庫

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

3. 安裝docker

sudo yum install -y docker-ce --allowerasing

##### 4. 啟動docker CE并設置開機自啟
```bash
sudo systemctl start docker
sudo systemctl enable docker

5.設置阿里云鏡像倉庫

sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://7kam90oa.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload
sudo systemctl restart docker

sudo systemctl status docker.service