To use the special agent of the checkmk which collects data from a NetApp filer instead of SNMP do the following:

1. Download the Netapp Manageability SDK from NetApp (a login is required). This can be downloaded here.
2. Login to OMD with su – sitename
3. Copy the two python files ‘NaElement.py’ and ‘NaServer.py’ to the OMD directory /omd/sites/sitename/local/lib/python
4. Add a new ruleset ‘Check NetApp via WebAPI’ for your filers. Make sure the user has appropiate permissions¹
5. Monitor your filer with a configured special agent instead of snmp or no agent

¹ The user which you use, needs appropriate permissions. The appropriate permissions can be found in the header of the agent (see also https://forum.checkmk.com/t/netapp-monitoring-via-checkmk/20694/6)

sources: https://checkmk.com/check_mk-werks.php?werk_id=1665