无法在Ubuntu 18.04上启动CUPS

Question

我在Ubuntu18.04仿生海狸上安装了像这样的杯子

$ sudo apt-get update
$ sudo apt-get install cups

我检查了杯子的状态，结果没有启动。

$ systemctl status cups

 ● cups.service - CUPS Scheduler
   Loaded: loaded (/lib/systemd/system/cups.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Mon 2018-09-10 16:29:40 EDT; 3s ago
     Docs: man:cupsd(8)
  Process: 2895 ExecStart=/usr/sbin/cupsd -l (code=exited, status=1/FAILURE)
 Main PID: 2895 (code=exited, status=1/FAILURE)

Sep 10 16:29:40 chrisni-X456UJ systemd[1]: cups.service: Service hold-off time over, scheduling restart.
Sep 10 16:29:40 chrisni-X456UJ systemd[1]: cups.service: Scheduled restart job, restart counter is at 5.
Sep 10 16:29:40 chrisni-X456UJ systemd[1]: Stopped CUPS Scheduler.
Sep 10 16:29:40 chrisni-X456UJ systemd[1]: cups.service: Start request repeated too quickly.
Sep 10 16:29:40 chrisni-X456UJ systemd[1]: cups.service: Failed with result 'exit-code'.
Sep 10 16:29:40 chrisni-X456UJ systemd[1]: Failed to start CUPS Scheduler.

我编辑了cupsd.conf，并将LogLevel从“警告”改为“调试”。我尝试手动启动cups，但是相同的输出重复。

$ systemctl start cups
$ systemctl status cups

这是log，显示的块是重复的。

$ grep cups /var/log/syslog

Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Failed with result 'exit-code'.
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Service hold-off time over, scheduling restart.
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Scheduled restart job, restart counter is at 1.
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Main process exited, code=exited, status=1/FAILURE
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Failed with result 'exit-code'.
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Service hold-off time over, scheduling restart.
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Scheduled restart job, restart counter is at 2.
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Main process exited, code=exited, status=1/FAILURE
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Failed with result 'exit-code'.
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Service hold-off time over, scheduling restart.
Sep 10 15:56:36 chrisni-X456UJ systemd[1]: cups.service: Scheduled restart job, restart counter is at 3.
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Main process exited, code=exited, status=1/FAILURE
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Failed with result 'exit-code'.
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Service hold-off time over, scheduling restart.
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Scheduled restart job, restart counter is at 4.
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Main process exited, code=exited, status=1/FAILURE
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Failed with result 'exit-code'.
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Service hold-off time over, scheduling restart.
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Scheduled restart job, restart counter is at 5.
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Start request repeated too quickly.
Sep 10 15:56:37 chrisni-X456UJ systemd[1]: cups.service: Failed with result 'exit-code'.
Sep 10 16:02:15 chrisni-X456UJ systemd[1]: cups.service: Main process exited, code=exited, status=1/FAILURE

有谁知道我怎么开始杯子的吗？

Answer 1

看看/var/log/cups/error_log的尾部：

X [14/Jul/2020:15:06:38 +0200] No valid Listen or Port lines were found in the configuration file.

实际上，配置文件被其他一些设置破坏了，但幸运的是保留了一个备份：

ll /etc/cups/cupsd.conf*
-rw-r----- 1 root 4571 2020-07-01 19:53 /etc/cups/cupsd.conf.O
-rw-r----- 1 root   22 2020-07-01 19:54 /etc/cups/cupsd.conf

这为我(在Ubuntu18.04中)恢复cupsd.conf和重新启动cups起了作用：

sudo -i
cd /etc/cups
cp cupsd.conf.O cupsd.conf
systemctl restart cups

通过下列方式核实：

systemctl status cups

Answer 2

我发现了系统未启动的系统错误。所以我搜索错误，然后去了https://linuxhandbook.com/system-has-not-been-booted-with-systemd/。因此，我使用的不是systemctl重启cups，而是使用service cups重新启动。然后使用service cups状态进行检查。一切都很好。