运行我的 puppet 脚本来安装 Sensu 时，出现此错误：
Error: Could not update: Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install sensu' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
The following NEW packages will be installed:
sensu
0 upgraded, 1 newly installed, 0 to remove and 145 not upgraded.
Need to get 22.1 MB of archives.
After this operation, 64.1 MB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
sensu
E: There are problems and -y was used without --force-yes
实际上，尝试运行“apt-get update”和“apt-get install sensu”时失败了
但是，当我在使用 vagrant 配置后在 ubuntu 终端中运行这些命令时，这两个命令都可以工作。