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