logging - Upstart 控制台输出不起作用

Question

我使用了 Upstart 为 console output 提供的示例.

/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

该消息存在于 /var/log/syslog ，但该消息未出现在控制台中。

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写信给 /dev/console ，默认情况下，它是系统虚拟日志记录设备: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 this Unix StackExchange question .

如果你真的想要，你可以改变什么 /dev/console通过修改引导配置指向:

# /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 console log节而不是 console output然后拖尾生成的文件。