docker: Error response from daemon: Get https://registry-1.docker.io/v2/: net/http: request canceled (Client.Timeout exceeded while awaiting headers).

解决方案：
1.

vim /etc/docker/daemon.json

{
   "registry-mirrors":["https://docker.mirrors.ustc.edu.cn"]
}

[root@ml] systemctl daemon-reload 
[root@ml] systemctl restart docker