docker pull very slow problem

## Ali cloud images using accelerator

[docker@web-test ~]$ cat /etc/docker/daemon.json
{
  "registry-mirrors": ["https://9cpn8tt6.mirror.aliyuncs.com"]
}
EOF

[docker@web-test ~]$ sudo systemctl daemon-reload
[docker@web-test ~]$ sudo systemctl restart docker

　　

verification:

[docker@web-test ~]$ docker pull nginx