Cuberite Forum

Can I external monitoring server via SNMP or another way (via Nagios, Zabbix, etc.)?
If create plugin needed - show me, please, class object to use.

It's not built in, you'd have to write a plugin for that. Since I have no idea how those technologies you mention work, I can't be more specific other than that you'll probably want to use the cNetwork class: http://luaapi.cuberite.org/cNetwork.html It supports both TCP and UDP lower protocols; you'll need to implement the actual application protocols used by those monitoring systems.