I found out the hard way that the user "zabbix" can only be used once in a VPS environment and that the first customer to define it in the hosting services' directory owns that user. The only alternatives are 1) allow agent to run as root or 2) hard-define the zabbix in /etc/[passwd|group] and lose the ability to configure other important users from the hoster's control panel. Please provide run-as-user definition in zabbix_agentd.conf or zabbix_proxy.conf (and zabbix_server, too, although this is perhaps debatable?). Debian/Ubuntu users may be able invoke this behaviour as an argument to start-stop-daemon in the init script, but i don't want to really have to modify the (RHEL) init script to su to the alternate user.