docker安装之后默认在 /etc/docker 

在/etc/docker 文件下有一个daemon -json

没有就新增

{"registry-mirrors": ["https://kfwkfulq.mirror.aliyuncs.com","https://2lqq34jg.mirror.aliyuncs.com","https://pee6w651.mirror.aliyuncs.com","https://registry.docker-cn.com","http://hub-mirror.c.163.com"],"log-opts": {"max-size": "500m","max-file": "3"},
"data-root": "/home/docker"
}

 然后 sudo docker info | grep "Docker Root Dir" 

Docker Root Dir 就是 /home/docker

如果不行就重启docker

  sudo systemctl start docker