Ubuntu – Zabbix file system autodiscovery does not kick in

If the agent is deployed active, and the FW allows each agent to connect back to the server on the correct port, you shouldn't have a problem getting alerts.

But if you have several agents behind a FW you should deploy a Zabbix Proxy, as Jacob mentioned.

Basic Zabbix concept - one item (check) = one value. Zabbix server doesn't provide parser functionality to parse multiple values, so it has to be always only one value.

If you want to return more value, than you have to use some workarounds, see zabbix UserParameter return 2 or more values

Zabbix sender example:

allow command execution in the zabbix-agent and create item (active or passive) to run your script:

system.run["myscript.sh > output_for_zabbix_sender.txt; zabbix_sender -s <host_name> -z <zabbix_server> -i output_for_zabbix_sender",nowait]

It will execute command in nowait mode. myscript.sh produces output in format:

hostname key1 value1
hostname key2 value2
...

And this output is processed (sent) to the zabbix server by zabbix_sender. Item type must be Zabbix trapper in this case (zabbix_sender). Eventually you don't need system.run item, you can execute script with zabbix_sender as cron job.

If you need perfect monitoring solution don't forget to handle errors, minimize IOPs, ...

You can use zabbix_sender also for discovering - just follow documentation about required format, e.g.:

hostname discovery_key {"data":[{"{#ID}": "/"},{"{#ID}":"/usr"},{"{#ID}":"/var"}]}