#inittab

[gslin]

當 Daemon 死掉時自動重新跑起...

當 Daemon 死掉時自動重新跑起…

以前確保 daemon 掛掉時會重新跑起來大概有幾個方式，像是用 Monit 顧，然後再用 /etc/inittab 確保 Monit 不會掛掉…

在 systemd 的年代，因為 systemd 已經被保護起來，而重跑這個功能在 systemd 裡就有支援，不需要用 Monit 這類程式了。

在 manual 裡搜尋 restart 可以看到幾個參數：

Restart=

RestartForceExitStatus=

RestartPreventExitStatus=

RestartSec=

這次是遇到 SmokePing 的 FastCGI daemon 每隔幾天會自己死掉，導致 nginx 丟出 503 然後被 UptimeRobot 偵測到而拋出警告。

但這個問題只有在一台伺服器會發生，而 log 裡也沒翻到可以繼續 debug 的錯誤訊息，試著猜測一些情境去搜尋引擎找也沒翻到……

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[amythical]

Raspi UART issues

Have trouble connecting UART to raspi, symptoms could be nothing displayed on screen, no prompt on login or hanging of screen after connecting.

Causes -

1.Nothing displayed on screen - logging could be disabled in boot cmdline

Fix - 

In /boot/cmdline.txt check if text is

dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait

2.No prompt on boot - getty respawn disabled

Fix - sudo vim /etc/inittab

Check for T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100

your serial terminal is usually ttyAMA0 and the corresponding line could vary depending on your baud rate (mine is 115200)

If this line is commented witha  #, remove the #.

3.You can login through UART but session hangs in between - Someother process could be hijacking your UART and writing to ttyAMA0.

Figure what process you have written uses serial communication and disable it.

[sevennet-blog]

Answer: Using inittab to ensure sshd (and other important items) are still running -- any drawbacks? #programming #dev #development

Answer: Using inittab to ensure sshd (and other important items) are still running — any drawbacks? #programming #dev #development

Using inittab to ensure sshd (and other important items) are still running any drawbacks?

Having managed to kill sshd on a remote machine (by running a script which used all available memory in the machine, oops…) which I have no access to other than visiting the hosting for[1], I was considering ways to ensure that sshd is always kept running.

Other than a hacky cron job to restart sshd every n…

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