# Ukážkový súbor k úlohe Z6.2 (kurz VPS a správa linuxového servera)
# Server "web1" (Debian 13). Vlastná služba, ktorá prevádzkuje malú webovú aplikáciu.

anna@web1:~$ systemctl status factuurapp
× factuurapp.service - Factuurapp (Node.js)
     Loaded: loaded (/etc/systemd/system/factuurapp.service; enabled; preset: enabled)
     Active: failed (Result: exit-code) since Mon 2026-11-09 10:15:07 CET; 12min ago
   Duration: 412ms
    Process: 2291 ExecStart=/usr/bin/node /opt/factuurapp/server.js (code=exited, status=1/FAILURE)
   Main PID: 2291 (code=exited, status=1/FAILURE)
        CPU: 389ms

anna@web1:~$ sudo journalctl -u factuurapp --since "2026-11-09 10:14" --no-pager
nov 09 10:15:01 web1 systemd[1]: Started factuurapp.service - Factuurapp (Node.js).
nov 09 10:15:01 web1 node[2240]: Factuurapp 3.2.0 start op 127.0.0.1:3000
nov 09 10:15:01 web1 node[2240]: Error: listen EADDRINUSE: address already in use 127.0.0.1:3000
nov 09 10:15:01 web1 node[2240]:     at Server.setupListenHandle [as _listen2] (node:net:1908:16)
nov 09 10:15:02 web1 systemd[1]: factuurapp.service: Main process exited, code=exited, status=1/FAILURE
nov 09 10:15:02 web1 systemd[1]: factuurapp.service: Failed with result 'exit-code'.
nov 09 10:15:03 web1 systemd[1]: factuurapp.service: Scheduled restart job, restart counter is at 1.
nov 09 10:15:03 web1 systemd[1]: Started factuurapp.service - Factuurapp (Node.js).
nov 09 10:15:03 web1 node[2252]: Error: listen EADDRINUSE: address already in use 127.0.0.1:3000
nov 09 10:15:03 web1 systemd[1]: factuurapp.service: Main process exited, code=exited, status=1/FAILURE
nov 09 10:15:03 web1 systemd[1]: factuurapp.service: Failed with result 'exit-code'.
nov 09 10:15:04 web1 systemd[1]: factuurapp.service: Scheduled restart job, restart counter is at 2.
nov 09 10:15:04 web1 systemd[1]: Started factuurapp.service - Factuurapp (Node.js).
nov 09 10:15:05 web1 node[2266]: Error: listen EADDRINUSE: address already in use 127.0.0.1:3000
nov 09 10:15:05 web1 systemd[1]: factuurapp.service: Main process exited, code=exited, status=1/FAILURE
nov 09 10:15:05 web1 systemd[1]: factuurapp.service: Failed with result 'exit-code'.
nov 09 10:15:06 web1 systemd[1]: factuurapp.service: Scheduled restart job, restart counter is at 3.
nov 09 10:15:06 web1 systemd[1]: Started factuurapp.service - Factuurapp (Node.js).
nov 09 10:15:06 web1 node[2279]: Error: listen EADDRINUSE: address already in use 127.0.0.1:3000
nov 09 10:15:06 web1 systemd[1]: factuurapp.service: Main process exited, code=exited, status=1/FAILURE
nov 09 10:15:06 web1 systemd[1]: factuurapp.service: Failed with result 'exit-code'.
nov 09 10:15:07 web1 systemd[1]: factuurapp.service: Scheduled restart job, restart counter is at 4.
nov 09 10:15:07 web1 systemd[1]: Started factuurapp.service - Factuurapp (Node.js).
nov 09 10:15:07 web1 node[2291]: Error: listen EADDRINUSE: address already in use 127.0.0.1:3000
nov 09 10:15:07 web1 systemd[1]: factuurapp.service: Main process exited, code=exited, status=1/FAILURE
nov 09 10:15:07 web1 systemd[1]: factuurapp.service: Failed with result 'exit-code'.
nov 09 10:15:07 web1 systemd[1]: factuurapp.service: Start request repeated too quickly.
nov 09 10:15:07 web1 systemd[1]: factuurapp.service: Failed with result 'exit-code'.
nov 09 10:15:07 web1 systemd[1]: Failed to start factuurapp.service - Factuurapp (Node.js).

anna@web1:~$ sudo ss -tlnp | grep 3000
LISTEN 0 511 127.0.0.1:3000 0.0.0.0:* users:(("node",pid=1187,fd=21))

Otázky:
1. Ako sa volá služba (unit)?
2. Koľkokrát bola služba celkovo spustená (riadky Started)?
3. S akým návratovým kódom (status) sa program ukončil?
4. Čo je podľa prvého chybového hlásenia príčinou?
   a. Chýba súbor server.js
   b. Port 3000 na 127.0.0.1 už používa iný proces
   c. Server má príliš málo pamäte
   d. Služba beží pod nesprávnym používateľom
5. O koľkej (hh:mm:ss) systemd vzdal opätovné spúšťanie?
6. Ktorý proces drží port obsadený (pid)?