Starting with version 4.0.15 systemd service file for Zabbix agent in official packages (https://www.zabbix.com/download) was updated to explicitly include directives for
Group. Both are set to
This means that old functionality of configuring which user Zabbix agent runs as via
zabbix_agentd.conf file is bypassed and agent will always run as the user specified in the systemd service file.
To override this new behavior create file
/etc/systemd/system/zabbix-agent.service.d/override.conf with the following content.
Reload daemons and restart zabbix-agent service.
For agent2 this completely determines the user that it runs as.
For old agent this only re-enables the functionality of configuring user in
zabbix_agentd.conf file. Therefore in order to run zabbix agent as root you still have to edit
zabbix_agentd.conf and specify
User=root as well as
AllowRoot=1 options. More on this here: https://www.zabbix.com/documentation/4.0/manual/appendix/config/zabbix_agentd.