Major With Zabbix 2.4.x, an empty LogFile configuration option meant "use syslog".
When upgrading to Zabbix 3.0, you have to set "LogType=system".
Not commenting LogFile option makes zabbix-agent start & fork, but a process is kept as zombie:
# ps fauxww | grep zabbix[_-]agent root 4263 0.0 0.0 4180 732 pts/0 S+ 16:51 0:00 | \_ /bin/sh /etc/init.d/zabbix-agent restart root 4288 0.0 0.0 4180 736 pts/0 S+ 16:51 0:00 | \_ /bin/sh /etc/init.d/zabbix-agent start zabbix 4296 0.0 0.0 0 0 pts/0 Z+ 16:51 0:00 | \_ [zabbix_agentd] <defunct> zabbix 4298 0.0 0.0 64824 932 ? S 16:51 0:00 /usr/sbin/zabbix_agentd zabbix 4299 0.0 0.0 64824 1048 ? S 16:51 0:00 \_ /usr/sbin/zabbix_agentd: collector [idle 1 sec] zabbix 4300 0.0 0.0 64824 1076 ? S 16:51 0:00 \_ /usr/sbin/zabbix_agentd: listener #1 [waiting for connection] zabbix 4301 0.0 0.0 64824 1052 ? S 16:51 0:00 \_ /usr/sbin/zabbix_agentd: listener #2 [waiting for connection] zabbix 4302 0.0 0.0 64824 944 ? S 16:51 0:00 \_ /usr/sbin/zabbix_agentd: listener #3 [waiting for connection] zabbix 4303 0.0 0.0 64824 688 ? S 16:51 0:00 \_ /usr/sbin/zabbix_agentd: active checks #1 [idle 1 sec]
Same behaviour occurs with zabbix_server. I haven't tested proxy yet, but I guess it would behave the same.
If LogType is set to system, Zabbix should completely ignore LogFile configuration option.