我最近从 14.04 更新到了 16.04。我的服务器上有 apache2，但最近我注意到了这一点：
fmf@kodi:~$ systemctl is-system-running
degraded
fmf@kodi:~$
因此我稍微挖掘一下：
fmf@kodi:~$ systemctl --state=failed
UNIT LOAD ACTIVE SUB DESCRIPTION
● apache2.service loaded failed failed LSB: Apache2 web server
LOAD = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB = The low-level unit activation state, values depend on unit type.
1 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
fmf@kodi:~$
然后再深入挖掘一下：
fmf@kodi:~$ systemctl status -l apache2.service
● apache2.service - LSB: Apache2 web server
Loaded: loaded (/etc/init.d/apache2; bad; vendor preset: enabled)
Drop-In: /lib/systemd/system/apache2.service.d
└─apache2-systemd.conf
Active: failed (Result: exit-code) since Wed 2016-08-03 14:57:11 CEST; 7min ago
Docs: man:systemd-sysv-generator(8)
Process: 3120 ExecStart=/etc/init.d/apache2 start (code=exited, status=1/FAILURE)
CGroup: /system.slice/apache2.service
├─3476 /usr/sbin/apache2 -k start
├─3479 /usr/sbin/apache2 -k start
├─3941 /usr/sbin/apache2 -k start
├─3942 /usr/sbin/apache2 -k start
├─3943 /usr/sbin/apache2 -k start
├─3944 /usr/sbin/apache2 -k start
├─3945 /usr/sbin/apache2 -k start
├─3965 /usr/sbin/apache2 -k start
├─3984 /usr/sbin/apache2 -k start
└─3985 /usr/sbin/apache2 -k start
Aug 03 14:56:38 kodi systemd[1]: Starting LSB: Apache2 web server...
Aug 03 14:56:38 kodi apache2[3120]: * Starting Apache httpd web server apache2
Aug 03 14:57:11 kodi apache2[3120]: *
Aug 03 14:57:11 kodi apache2[3120]: * The apache2 instance did not start within 20 seconds. Please read the log files to discover problems
Aug 03 14:57:11 kodi systemd[1]: apache2.service: Control process exited, code=exited status=1
Aug 03 14:57:11 kodi systemd[1]: Failed to start LSB: Apache2 web server.
Aug 03 14:57:11 kodi systemd[1]: apache2.service: Unit entered failed state.
Aug 03 14:57:11 kodi systemd[1]: apache2.service: Failed with result 'exit-code'.
fmf@kodi:~$
奇怪的是，如果我尝试连接到服务器上的网页，我可以看到它。这个错误来自哪里？我尝试检查 apache2 日志，但没有发现任何奇怪的东西。
也许这有帮助：
fmf@kodi:~$ netstat -antp | grep 80
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN 3929/kodi.bin
tcp 0 1 192.168.254.8:47306 144.76.30.184:80 SYN_SENT 3929/kodi.bin
tcp 0 160 192.168.254.8:46574 144.76.30.184:80 ESTABLISHED 3929/kodi.bin
tcp 0 156 192.168.254.8:46836 144.76.30.184:80 ESTABLISHED 3929/kodi.bin
tcp 0 165 192.168.254.8:47268 144.76.30.184:80 ESTABLISHED 3929/kodi.bin
tcp 0 166 192.168.254.8:47232 144.76.30.184:80 FIN_WAIT1 -
tcp 0 165 192.168.254.8:47112 144.76.30.184:80 ESTABLISHED 3929/kodi.bin
tcp 0 1 192.168.254.8:47304 144.76.30.184:80 SYN_SENT 3929/kodi.bin
tcp 0 1 192.168.254.8:47302 144.76.30.184:80 SYN_SENT 3929/kodi.bin
tcp 1 0 192.168.254.8:38502 104.20.56.43:80 CLOSE_WAIT 3176/python
tcp 0 1 192.168.254.8:47292 144.76.30.184:80 SYN_SENT 3929/kodi.bin
tcp 0 166 192.168.254.8:47252 144.76.30.184:80 FIN_WAIT1 -
tcp 0 1 192.168.254.8:47294 144.76.30.184:80 SYN_SENT 3929/kodi.bin
tcp6 0 0 :::8080 :::* LISTEN 3929/kodi.bin
tcp6 0 0 :::80 :::* LISTEN -
tcp6 0 0 192.168.254.8:80 77.108.48.106:61805 TIME_WAIT -
tcp6 0 0 192.168.254.8:80 77.108.48.106:61851 TIME_WAIT -
fmf@kodi:~$
请问有什么帮助吗？
答案1
您也可以尝试：
sudo systemctl reset-failed
reset-failed [PATTERN...]
Reset the "failed" state of the specified units, or if no unit name is passed, reset the state of all units. When a unit
fails in some way (i.e. process exiting with non-zero error code, terminating abnormally or timing out), it will
automatically enter the "failed" state and its exit code and status is recorded for introspection by the administrator
until the service is stopped/re-started or reset with this command.
In addition to resetting the "failed" state of a unit it also resets various other per-unit properties: the start rate
limit counter of all unit types is reset to zero, as is the restart counter of service units. Thus, if a unit's start
limit (as configured with StartLimitIntervalSec=/StartLimitBurst=) is hit and the unit refuses to be started again, use
this command to make it startable again.