Bash – inittab respawn and rc.local

bashdaemoninitinit-script

At the moment I have a daemon starting at boot using rc.local by the following line.

su -l user -c '/dir/daemon'

but I would like to start this process as a service with respawn. I found out that it should be added to /etc/inittab with something like

daemon:run-level:respawn:script-to-daemon

which run level should I use?
how do I have it executed as user?
if I'm using inittab should I remove the line in rc.local
is there something like forever that'll do this for me

Best Answer

Forget about `/etc/inittab`.

If you have Ubuntu with upstart, or one of the systemd operating systems, then your system completely ignores /etc/inittab and it is a complete irrelevance.

Scott James Remnant and James Hunt. inittab(5). Ubuntu version 12 manual pages.
https://unix.stackexchange.com/a/196197/5132

Forget about runlevels.

They exist in systemd operating systems, but only as compatibility shims. The systemd documentation states that the concept is "obsolete". If you're starting with this on a systemd operating system, don't start there.

https://unix.stackexchange.com/a/196014/5132

Forget about `forever`.

If you have a service manager, be it runit, systemd, perp, nosh, upstart, s6, or daemontools-encore, then it's already doing what you think you need forever for.

https://askubuntu.com/a/625378/43344

Take your stuff out of `rc.local`.

On an upstart or systemd system it's really as much of a compatibility shim as runlevels are.

Put your stuff into an upstart job or a systemd service unit.

The latter would look something like

[Unit]
Description=Start the wibble daemon

[Service]
User=wibble-d
ExecStart=/usr/local/bin/wibbled
Restart=always

[Install]
WantedBy=multi-user.target

Related Solutions

Ubuntu – Running a command at startup

1) I'm afraid that it's the latter. But don't feel bad, most people trip over it.

2+3) The only ones that would have a chance of working are 5 and 8. The startup scripts and cron have no idea of your login session, so there's no way they could point remind or gmessage in the right direction. And 5 didn't work because the ampersand at the end is a feature of the shell, not the command. You likely don't even need it if the command is being run as a startup application.

Linux – How Do I Add My Own Daemons in Arch Linux? (BSD-style init)

What does update-rc.d to do with Arch ? that's for debian based distros.

A sample script, put it in /etc/rc.d/XX and make it executable, and edit /etc/rc.conf, push the name of the service into DAEMONS array

#!/bin/sh

. /etc/rc.conf
. /etc/rc.d/functions

case "$1" in
        stop)
                stat_busy "Stopping XX"
                command_to_exec && rm_daemon XX && stat_done || stat_fail
                ;;
        start)
                stat_busy "Starting XXX"
                command_to_exec && add_daemon XX && stat_done || stat_fail
                ;;

esac

exit 0

If you're not seeing the daemon in list, you've probably missed the add_daemon function

Best Answer

Forget about /etc/inittab.