docker配置国内源后重启失败Job for docker.service failed because start of the service was attempted too often。

背景
刚装的docker，忘了配源。下载直接超时。
配置了一下源。
重启报错
Job for docker.service failed because start of the service was attempted too often. See "systemctl status docker.service" and "journalctl -xe" for details. To force a start use "systemctl reset-failed docker.service" followed by "systemctl start docker.service" again

解决方案：
删掉daemon.json，用root执行下面语句。
tee /etc/docker/daemon.json <<-'EOF'
{

"registry-mirrors": [
    "https://docker.m.daocloud.io",
    "https://dockerproxy.com",
    "https://docker.mirrors.ustc.edu.cn",
    "https://docker.nju.edu.cn"
]

}

EOF
再执行
systemctl daemon-reload
systemctl restart docker
成功