Trying to run a game server as a service

Question

I'm trying to use monit to check my game server and restart it if it fails. The monit part is fairly simple to check port 28960 but I'm struggling to run the start script (cod4.sh) if monit detects a fail.

so far I have: monitrc:

    set daemon  60
# set log /var/log/monit.log
set mailserver 127.0.0.1
# set mail-format { from: monit@mydomain }
set alert [email protected]
set httpd port 2812
   allow alec:password

check host dels with address 127.0.0.1
start program = "/bin/systemctl start cod4"
stop program = "/bin/systemctl stop cod4"

if failed port 28960 then restart`

This works and I get en e-mail if I kill the server.

I created a service file cod4.service

[Unit]
Description=Cod4 service

[Service]
User=cod4
Type=forking
ExecStart=/cod4-linux-server/cod4.sh


[Install]
WantedBy=multi-user.target

cod4.sh consists of

#!/bin/bash
screen -dmS cod4 ./cod4x18_dedrun +set r_xassetnum "xmodel=1200" +set sv_authorizemode "0" + set sv_maxclients "64" +set fs_game "mods/rotu2beta" +exec server.cfg +map_rotate

When I try to start the server with service cod4 start nothing happens, I'm probably going about this in the wrong way or over complicating it as usual by piecing together code from different sites.

Basically monit checks port 28960 and needs to run cod4.sh if there is a failure.

Any ideas please.

A little progress I think,

systemctl daemon-reload
systemctl enable cod4.service

I now get

systemctl status cod4
● cod4.service - Cod4 service
   Loaded: loaded (/lib/systemd/system/cod4.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Mon 2019-11-11 16:01:22 EST; 52s ago
  Process: 17788 ExecStart=/cod4-linux-server/cod4.sh (code=exited, status=0/SUCCESS)
 Main PID: 17790 (code=exited, status=0/SUCCESS)

This would suggest that it did indeed execute the cod4.sh then exit as it should, however lsof -i as user cod4 tells me the server is not running.

So whats the difference between su cod4 cd/cod4-linux-server ./cod4.sh which loads the server correctly and

[Service]
User=cod4
Type=forking
ExecStart=/cod4-linux-server/cod4.sh


[Install]
WantedBy=multi-user.target

Answer 1

Thank-you Kamil you nailed it with your first comment and made me aware of yet another strange thing about Ubuntu, let me explain what was going on here.

Monit was working as it should, the cod4.service file is correct and it did indeed run when asked.

When the service runs it looks for the cod4.sh script in /cod4-linux-server/ and it finds it OK BUT inside the script was ./cod4x18_dedrun and for some reason it couldn't find it. Changing it to /cod4-linux-server/cod4x18_dedrun did the job.

So if you run a script from a systemd and the script is in the same folder as the binary it launches you still need to be absolute with the binary path!

Cheers