@linuxmaniac changes is not required. I updated kamailio config and now daemon cannot parse config. System unit not restart as exist `start-limit`
[root@aeyears kamailio]# systemctl status kamailio ● kamailio.service - Kamailio (OpenSER) - the Open Source SIP Server Loaded: loaded (/usr/lib/systemd/system/kamailio.service; enabled; vendor preset: disabled) Active: failed (Result: start-limit) since Sat 2017-04-29 10:20:45 EDT; 4min 50s ago Process: 99917 ExecStart=/usr/sbin/kamailio -P /run/kamailio/kamailio.pid -f $CFGFILE -m $SHM_MEMORY -M $PKG_MEMORY (code=exited, status=255) Main PID: 99614 (code=exited, status=0/SUCCESS)
Apr 29 10:20:44 aeyears.as50056.net systemd[1]: Failed to start Kamailio (OpenSER) - the Open Source SIP Server. Apr 29 10:20:44 aeyears.as50056.net systemd[1]: Unit kamailio.service entered failed state. Apr 29 10:20:44 aeyears.as50056.net systemd[1]: kamailio.service failed. Apr 29 10:20:45 aeyears.as50056.net systemd[1]: kamailio.service holdoff time over, scheduling restart. Apr 29 10:20:45 aeyears.as50056.net systemd[1]: start request repeated too quickly for kamailio.service Apr 29 10:20:45 aeyears.as50056.net systemd[1]: Failed to start Kamailio (OpenSER) - the Open Source SIP Server. Apr 29 10:20:45 aeyears.as50056.net systemd[1]: Unit kamailio.service entered failed state. Apr 29 10:20:45 aeyears.as50056.net systemd[1]: kamailio.service failed.