Steps to reproduce:

1. run agent2 container on host whiel mapping '/var/run/dbus/system_bus_socket:/var/run/dbus/system_bus_socket:rw'
2. assign template "Systemd by Zabbix agent 2" to host object in Zabbix
3. check discovery of items for this host: service units, socket units

Result:

the discovery does not work with error info: Cannot establish connection to any available bus: dbus: authentication failed

however, the zabbix-agent2 container as r/w permissions for the dbus socket, as properly mapped (see (1.))

Expected:
service units and socket units should be discovered from systemd