server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none failed

• 问题：在Ubuntu16.04环境下执行apt update时,The certificate authentication of the feedback service host failed.

错误:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 systemd-sysv amd64 229-4ubuntu21.31
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
错误:2 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 libpam-systemd amd64 229-4ubuntu21.31
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
错误:3 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 libsystemd0 amd64 229-4ubuntu21.31
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
错误:4 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 systemd amd64 229-4ubuntu21.31
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
错误:5 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 udev amd64 229-4ubuntu21.31
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
错误:6 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 libudev1 amd64 229-4ubuntu21.31
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
错误:7 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 libseccomp2 amd64 2.5.1-1ubuntu1~16.04.1
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none

• 解决办法：

1. 在 /etc/apt/apt.conf.d目录下创建99verify-peer.conf配置文件

   # touch /etc/apt/apt.conf.d/99verify-peer.conf
   

2. Enter the following line into the file：Acquire { https::Verify-Peer false }

   # vim /etc/apt/apt.conf.d/99verify-peer.conf 
   

3. save reloadhttpsNetwork transmission authentication certificate

apt install apt-transport-https ca-certificates
正在读取软件包列表... 完成
正在分析软件包的依赖关系树
正在读取状态信息... 完成
ca-certificates 已经是最新版 (20210119~16.04.1).
下列软件包将被升级：
  apt-transport-https
升级了 1 个软件包,新安装了 0 个软件包,要卸载 0 个软件包,有 24 个软件包未被升级.
需要下载 26.6 kB 的归档.
解压缩后会消耗 1,024 B 的额外空间.
您希望继续执行吗？ [Y/n] y
获取:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 apt-transport-https amd64 1.2.35 [26.6 kB]
已下载 26.6 kB,耗时 19秒 (1,397 B/s)
(正在读取数据库 ... 系统当前共安装有 186842 个文件和目录.)
正准备解包 .../apt-transport-https_1.2.35_amd64.deb  ...
正在将 apt-transport-https (1.2.35) 解包到 (1.2.32ubuntu0.2) 上 ...
正在设置 apt-transport-https (1.2.35) ...

4. Re-execute the software list and update commands

apt update
命中:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial InRelease
命中:2 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates InRelease
命中:3 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-backports InRelease
命中:4 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-security InRelease
正在读取软件包列表... 完成
正在分析软件包的依赖关系树
正在读取状态信息... 完成
有 26 个软件包可以升级.请执行 ‘apt list --upgradable’ 来查看它们.
apt upgrade
正在读取软件包列表... 完成
正在分析软件包的依赖关系树
正在读取状态信息... 完成
正在计算更新... 完成
下列【新】软件包将被安装：
  distro-info libzstd1 python3-distro-info python3-yaml
下列软件包将被升级：
  apt apt-utils dpkg dpkg-dev grub-common grub-pc grub-pc-bin grub2-common libapt-inst2.0 libapt-pkg5.0 libdpkg-perl libgnutls-openssl27 libgnutls30 libpam-systemd
  libseccomp2 libsystemd0 libudev1 python-apt-common python3-apt systemd systemd-sysv ubuntu-advantage-tools udev unattended-upgrades update-notifier
  update-notifier-common
升级了 26 个软件包,新安装了 4 个软件包,要卸载 0 个软件包,有 0 个软件包未被升级.
需要下载 15.2 MB 的归档.
解压缩后会消耗 3,870 kB 的额外空间.
您希望继续执行吗？ [Y/n] y
获取:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 libzstd1 amd64 1.3.1+dfsg-1~ubuntu0.16.04.1 [153 kB]
获取:2 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates/main amd64 dpkg amd64 1.18.4ubuntu1.7 [2,084 kB]

• 由此看出,已经完美解决！