How to make sure an application keeps running on Linux

Question

I'm trying to ensure a script remains running on a development server. It collates stats and provides a web service so it's supposed to persist, yet a few times a day, it dies off for unknown reasons. When we notice we just launch it again, but it's a pain in the rear and some users don't have permission (or the knowhow) to launch it up.

The programmer in me wants to spend a few hours getting to the bottom of the problem but the busy person in me thinks there must be an easy way to detect if an app is not running, and launch it again.

I know I could cron-script ps through grep:

ps -A | grep appname

But again, that's another hour of my life wasted on doing something that must already exist... Is there not a pre-made app that I can pass an executable (optionally with arguments) and that will keep a process running indefinitely?

In case it makes any difference, it's Ubuntu.

Answer 1

I have used a simple script with cron to make sure that the program is running. If it is not, then it will start it up. This may not be the perfect solution you are looking for, but it is simple and works rather well.

#!/bin/bash
#make-run.sh
#make sure a process is always running.

export DISPLAY=:0 #needed if you are running a simple gui app.

process=YourProcessName
makerun="/usr/bin/program"

if ps ax | grep -v grep | grep $process > /dev/null
then
    exit
else
    $makerun &
fi

exit

Then add a cron job every minute, or every 5 minutes.