我有 2 个计算引擎实例：
一个跑了半年左右，今天第一次得到：
Err:11 http://packages.cloud.google.com/apt google-cloud-packages-archive-keyring-stretch InRelease The following signatures couldn't be verified because the public key is not available:
另一个我今天刚刚从一个干净的 Debian 9 映像设置，它不允许我 apt-get 安装任何东西：
E: Unable to locate package php7.2-fpm
E: Couldn't find any package by glob 'php7.2-fpm'
E: Couldn't find any package by regex 'php7.2-fpm'
以前没有那个。