Ubuntu – How to make a jar file run on startup & and when you log out

javalogoutservicesstartup

I have no idea where to start looking. I've been reading about daemons and didn't understand the concept.

More details :

  • I've been writing a crawler which never stops and crawlers over RSS in the internet.
  • The crawler has been written in java – therefore its a jar right now.
  • I'm an administrator on a machine that has Ubuntu 11.04 .
  • There is some chances for the machine to crash , so I'd like the crawler to run every time you startup the machine.
  • Furthermore, I'd like it to keep running even when i logged out. I'm not sure this is possible, but most of the time I'm logged out, and I still want to it crawl.

Any ideas? Can someone point me in the right direction?

Just looking for the simplest solution.

Best Answer

Here's a easy way to do that using SysVInit. Instructions:

  1. Create the start and the stop script of your application. Put it on some directory, in our example is:

    • Start Script: /usr/local/bin/myapp-start.sh
    • Stop Script: /usr/local/bin/myapp-stop.sh

    Each one will provide the instructions to run/stop the app. For instance the myapp-start.sh content can be as simple as the following: 

    #!/bin/bash

java -jar myapp.jar

    For the stop script it can be something like this:

    #!/bin/bash
# Grabs and kill a process from the pidlist that has the word myapp

pid=`ps aux | grep myapp | awk '{print $2}'`
kill -9 $pid

  2. Create the following script (myscript) and put it on /etc/init.d.

    /etc/init.d/myscript content:

    #!/bin/bash
# MyApp
#
# description: bla bla

case $1 in
    start)
        /bin/bash /usr/local/bin/myapp-start.sh
    ;;
    stop)
        /bin/bash /usr/local/bin/myapp-stop.sh
    ;;
    restart)
        /bin/bash /usr/local/bin/myapp-stop.sh
        /bin/bash /usr/local/bin/myapp-start.sh
    ;;
esac
exit 0

  3. Put the script to start with the system (using SysV). Just run the following command (as root):

    update-rc.d myscript defaults

PS: I know that Upstart is great and bla bla, but I preffer the old SysV init system.

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