OpenVPN配置错误导致不能正常升级

sudo apt-get update 
sudo apt-get upgrade

报错

Setting up procps (2:3.3.9-9+deb8u1) ...
Job for systemd-sysctl.service failed. See 'systemctl status systemd-sysctl.service' and 'journalctl -xn' for details.
invoke-rc.d: initscript procps, action "start" failed.
dpkg: error processing package procps (--configure):
subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of udev:
udev depends on procps; however:
Package procps is not configured yet.

dpkg: error processing package udev (--configure):
dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of systemd:
systemd depends on udev (>= 208-8); however:
Package udev is not configured yet.

dpkg: error processing package systemd (--configure):
dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of initramfs-tools:
initramfs-tools depends on udev; however:
Package udev is not configured yet.

dpkg: error processing package initramfs-tools (--configure):
dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of systemd-sysv:
systemd-sysv depends on systemd (= 215-17+deb8u7); however:
Package systemd is not configured yet.
systemd-sysv depends on systemd; however:
Package systemd is not configured yet.

dpkg: error processing package systemd-sysv (--configure):
dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of openssh-server:
openssh-server depends on procps; however:
Package procps is not configured yet.

dpkg: error processing package openssh-server (--configure):
dependency problems - leaving unconfigured
Errors were encountered while processing:
procps
udev
systemd
initramfs-tools
systemd-sysv
openssh-server

虽然看起来有很多错误, 我们一般从头开始排查, 注意这句:

Job for systemd-sysctl.service failed. See 'systemctl status systemd-sysctl.service' and 'journalctl -xn' for details.
于是我们按照提示

 sudo systemctl status systemd-sysctl.service

看到

● systemd-sysctl.service - Apply Kernel Variables
Loaded: loaded (/lib/systemd/system/systemd-sysctl.service; static)
Active: failed (Result: exit-code) since Thu 2018-11-01 09:34:57 CST; 1min 0s ago
Docs: man:systemd-sysctl.service(8)
man:sysctl.d(5)
Process: 1562 ExecStart=/lib/systemd/systemd-sysctl (code=exited, status=1/FAILURE)
Main PID: 1562 (code=exited, status=1/FAILURE)

Nov 01 09:34:57 xxxx systemd[1]: Starting Apply Kernel Variables...
Nov 01 09:34:57 xxxx systemd[1]: systemd-sysctl.service: main process exited, code=exited, status=1/FAILURE
Nov 01 09:34:57 xxxx systemd[1]: Failed to start Apply Kernel Variables.
Nov 01 09:34:57 xxxx systemd[1]: Unit systemd-sysctl.service entered failed state.

主要是这句:

Failed to start Apply Kernel Variables.
其实就是说我们的sysctl配置中有些内核变量不能正常使用. 于是查看sysctl配置

 cat /etc/sysctl.conf |grep '^[^#;]'

看到

net.ipv4.ip_forward=1
net.ipv6.conf.all.forwarding=1
net.netfilter.nf_conntrack_max=64000
net.nf_conntrack_max=64000
将它们注释掉, 然后再次

sudo apt-get update 
sudo apt-get upgrade

升级成功.