I verify that the debug file is empty.
[root@localhost nagios]# touch /usr/local/nagios/var/ndo2db.debug
[root@localhost nagios]# chmod 644 /usr/local/nagios/var/ndo2db.debug
[root@localhost nagios]# chown nagios.nagios /usr/local/nagios/var/ndo2db.debug
[root@localhost nagios]# service ndo2db restart
Redirecting to /bin/systemctl restart ndo2db.service
[root@localhost nagios]# ll /usr/local/nagios/var/ndo2db.debug
-rw-r--r-- 1 nagios nagios 0 ago 22 16:30 /usr/local/nagios/var/ndo2db.debug
[root@localhost nagios]# service ndo2db status -l
Redirecting to /bin/systemctl status -l ndo2db.service
â— ndo2db.service - Nagios Data Out Daemon
Loaded: loaded (/usr/lib/systemd/system/ndo2db.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since mié 2018-08-22 16:33:19 -05; 1min 7s ago
Docs:
http://www.nagios.org/documentation
Process: 15820 ExecStopPost=/bin/rm -f /usr/local/nagios/var/ndo2db.pid (code=exited, status=0/SUCCESS)
Process: 15813 ExecStart=/usr/local/nagios/bin/ndo2db -c /usr/local/nagios/etc/ndo2db.cfg -f (code=exited, status=1/FAILURE)
Main PID: 15813 (code=exited, status=1/FAILURE)
ago 22 16:33:19 localhost.localdomain systemd[1]: Started Nagios Data Out Daemon.
ago 22 16:33:19 localhost.localdomain systemd[1]: Starting Nagios Data Out Daemon...
ago 22 16:33:19 localhost.localdomain ndo2db[15813]: Could not bind socket: Address already in use
ago 22 16:33:19 localhost.localdomain systemd[1]: ndo2db.service: main process exited, code=exited, status=1/FAILURE
ago 22 16:33:19 localhost.localdomain systemd[1]: Unit ndo2db.service entered failed state.
ago 22 16:33:19 localhost.localdomain systemd[1]: ndo2db.service failed.
[root@localhost nagios]#