centos8 Failed to get properties: Access denied

Failed to start docker.service: Access denied

今天在centos8上安装docker，参考以下网址

Centos7上安装docker - 风止雨歇 - 博客园

安装完了运行docker info显示错误

Server:
ERROR: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
errors pretty printing info

找了N多解决方案，什么daemon.json的、yum update的、systemctl start docker的都白搭，而且运行任何的systemctl命令都被拒绝，显示Failed to start docker.service: Access denied

最后找到个解决方案 

centos - systemctl access denied when root - Super User

In my case, I had just upgraded systemd and any systemctl command was failing:

# systemctl daemon-reexec
Failed to reload daemon: Access denied
# systemctl status
Failed to read server status: Access denied

However according to the init manpage, you can do the same thing by sending SIGTERM to the daemon running as PID 1, which worked:

kill -TERM 1

This reloaded the daemon, after which all the systemctl commands started working again.