Ubutntu安装docker启动报Removed /etc/systemd/system/docker.service.的错误，只需要执行以下三条命令。
systemctl unmask docker.service
systemctl unmask docker.socket
systemctl start docker.service
Ubutntu安装docker启动报Removed /etc/systemd/system/docker.service.
原文：https://www.cnblogs.com/li-bing/p/9245783.html