Upstart控制台输出无法正常工作

Question

我使用Upstart提供的控制台输出示例.

/etc/init/test.conf

console output

pre-start script

  # Perform whatever checks you like here (maybe checking
  # '/etc/default/foo' to see if the service is enabled # or not).
  #
  # if there are no problems detected, simply "exit 0", else do
  # something like this...

  # display an error message to stderr *on the console* and also write
  # the same message to the system log.
  logger -is -t "$UPSTART_JOB" "ERROR: foo!"

  # tell Upstart not to start the main process for the job.
  exit 1
end script

# this service doesn't do much :-)
exec sleep 999

然后作为根

$ initctl start test
initctl: Job failed to start

消息存在/var/log/syslog,但控制台中不存在该消息.

Jul 23 07:42:19 paul test[26595]: ERROR: foo!

---

如何将错误记录到控制台？

这是Ubuntu 14.04,

$ initctl version
init (upstart 1.12.1)

Answer 1

console output写入/dev/console，默认情况下，它是系统虚拟日志设备：它不会写入您的个人控制台（例如/dev/tty0）。

如果您尝试直接写入这些虚拟设备，您实际上可以测试行为的差异：

sudo echo test >> /dev/console     # Won't work
sudo su; echo test >> /dev/console # Works but nothing prints
sudo echo test >> /dev/tty0        # Works and prints

有关不同虚拟控制台设备之间差异的更多信息，请参阅此 Unix StackExchange 问题。

如果您确实愿意，可以/dev/console通过修改引导配置来更改指向的内容：

# /etc/default/grub

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.

GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,115200n8"

...但如果我是你，我只会使用该console log节而不是console output然后尾部生成的文件。