环境

镜像版本ubuntu-18.04.6-live-server-amd64.iso

系统环境

root@mq3:~#cat /etc/os-release 
NAME="Ubuntu"
VERSION="18.04.6 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.6 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

起因

开机之后发现系统资源占用特别高

root@mq3:~#top
top - 07:44:55 up 8 min,  1 user,  load average: 1.22, 0.56, 0.25
Tasks: 208 total,   2 running,  96 sleeping,   0 stopped,   0 zombie
%Cpu(s): 10.5 us,  8.1 sy,  4.4 ni, 74.6 id,  1.7 wa,  0.0 hi,  0.7 si,  0.0 st
KiB Mem :  4015804 total,  2498928 free,   323476 used,  1193400 buff/cache
KiB Swap:  4015100 total,  4015100 free,        0 used.  3436288 avail Mem 

   PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                                                      
 32282 root      39  19  214672 141316 100280 R  15.0  3.5   0:00.45 apt-check                                                    
  2592 root      20   0  428820 179248 103984 S  13.7  4.5   0:47.59 unattended-upgr                                              
 31566 root      20   0  428820 121020  45752 S   6.3  3.0   0:00.19 unattended-upgr                                              

查了一下这个unattended-upgr是ubuntu的无人值守自动更新系统

root@kktb:~#dpkg -l unattended-upgrades
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                       Version            Architecture       Description
+++-==========================-==================-==================-==========================================================
ii  unattended-upgrades        1.1ubuntu1.18.04.1 all                automatic installation of security upgrades
# 自动安装安全升级

关闭自动更新

sudo dpkg-reconfigure unattended-upgrades

大概意思：
经常应用更新是保证系统安全的重要组成部分。 默认情况下，需要应用更新手工使用软件包管理工具。 或者，您可以选择让这个系统自动下载和安装重要更新。
自动下载并安装稳定的更新?

选择否

会有一个报错

sudo dpkg-reconfigure unattended-upgrades

Replacing config file /etc/apt/apt.conf.d/20auto-upgrades with new version
dpkg: error: dpkg frontend is locked by another process

dpkg前台被另一个进程锁定

删除锁

rm -rf /var/cache/apt/archives/lock
rm -rf /var/lib/dpkg/lock-frontend

重新配置一下dpkg

root@kktb:~#sudo dpkg --configure -a

再次执行sudo dpkg-reconfigure unattended-upgrades即可

卸载无人值守自动更新

sudo apt remove unattended-upgrades -y

手动更新

apt update && apt upgrade

参考：Ubuntu关闭无人值守自动跟新