debian varnish service is masked 解决办法

使用debian 安装varnish,原先安装的是varnish4.0,之后想安装5.2版本。运行:

sudo service varnish restart

报错：

Failed to start varnish.service: Unit varnish.service is masked.

解决 办法：

 sudo systemctl unmask varnish.service
 sudo systemctl enable varnish.service
 sudo systemctl restart varnish.service