Distributor ID: Ubuntu
Description: Ubuntu 18.04.2 LTS
Release: 18.04
Codename: bionic
在无人值守升级期间，CPU 使用 100% 的资源达 4 小时
例子：
无人值守升级 --dry-run --debug
2019-02-16 10:34:46,087 INFO Enabled logging to syslog via daemon facility
2019-02-16 10:34:46,087 INFO Initial blacklisted packages:
2019-02-16 10:34:46,088 INFO Initial whitelisted packages:
2019-02-16 10:34:46,088 INFO Starting unattended upgrades script
2019-02-16 10:34:46,088 INFO Allowed origins are: o=Ubuntu,a=bionic, o=Ubuntu,a=bionic-security, o=UbuntuESM,a=bionic
2019-02-16 10:34:56,044 INFO Enabled logging to syslog via daemon facility
2019-02-16 10:34:56,045 INFO Initial blacklisted packages:
2019-02-16 10:34:56,045 INFO Initial whitelisted …