Run jar file as Daemon on Linux Ubuntu - linux

Question

I want to install a bot to my Teamspeak3 and run this bot as a daemon on startup. I wrote my own script and copied it to init.d and then added it with update-rc.d to defaults.
#!/bin/sh
#
# JTS3ServerBot Script
#
USER="ts"
NAME="jts3"
DIR="/home/ts/jts3/"
case $1 in
start)
echo "Starting ${NAME} ..."
if [ ! -f $DIR/pid ]; then
sudo -u $USER -c nohup java -jar $DIR/JTS3ServerMod.jar $DIR 2>> /dev/null >> /dev/null &
echo $! > $DIR/pid
echo "${NAME} started ..."
else
echo "${NAME} is already running ..."
fi
;;
stop)
if [ -f $DIR/pid ]; then
PID=$(cat $DIR/pid);
echo "Stopping ${NAME} ..."
kill $PID;
echo "${NAME} stopped ..."
rm $DIR/pid
else
echo "${NAME} is not running ..."
fi
;;
restart)
if [ -f $DIR/pid ]; then
PID=$(cat $DIR/pid);
echo "Stopping ${NAME} ...";
kill $PID;
echo "${NAME} stopped ...";
rm $DIR/pid
echo "Starting ${NAME} ..."
sudo -u $USER -c nohup java -jar $DIR/JTS3ServerMod.jar $DIR 2>> /dev/null >> /dev/null &
echo $! > $DIR/pid
echo "${NAME} started ..."
else
echo "${NAME} is not running ..."
fi
;;
esac
A pid file in generated, but if i try to kill the process with this pid i get an error that the process does not exist. If i use top there is no process with the pid listed.
root#vps-1023645-8462:~# service jts3 start
Starting jts3 ...
jts3 started ...
root#vps-1023645-8462:~# cat /home/ts/jts3/pid
10206
root#vps-1023645-8462:~# kill 10206
bash: kill: (10206) - No such process
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1762 ts 20 0 1881m 14m 3408 S 0 1.4 215:47.28 ts3server_linux
32356 ts 20 0 164m 1576 1336 S 0 0.2 0:09.85 tsdnsserver_lin

Answer 1

I have found another solution for my problem. I use upstart (works only with Ubuntu) to run my jar-File as a daemon. Upstart manages the PIDs. Just add myservice.conf to /etc/init (not /etc/inid.d) and the daemon will be started on boot and you can mangage it as a service. You do not have to make the file runnable or anything else
You can manage the service as normal for example
service myservice restart
service myservice status
...
My Config-File:
description "myservice"
author "your name"
start on runlevel [3]
stop on shutdown
expect fork
script
cd /home/username/
sudo -u username java -jar /home/username/myservice/myservice.jar >/home/username/myservice.log 2>&1
emit myservice_running
end script
This solution is really easy and works well on my Ubuntu 12.04 Server.

Answer 2

You have an error in this line:
sudo -u $USER -c nohup java -jar $DIR/JTS3ServerMod.jar $DIR 2>>/dev/null >>/dev/null&
You appear to be mixing the syntaxes of sudo and su. Before version 1.8, sudo had no -c option - you just give it the command to run after any other options. In 1.8 there is a -c option but it's not for specifying the command (it's for limiting resource usage to that of a given login class). sudo is printing an error message about this invalid syntax, but you're not seeing it because you're redirecting all the output to /dev/null.
Simply remove the -c to form a valid command:
sudo -u $USER nohup java -jar $DIR/JTS3ServerMod.jar $DIR 2>> /dev/null >> /dev/null &
Also, you can simplify the command a little by using the 2>&1 syntax to send stderr to the same handle as stdout, and there is no need for append mode when writing to /dev/null:
sudo -u $USER nohup java -jar $DIR/JTS3ServerMod.jar $DIR >/dev/null 2>&1 &