As Custom OID cannot accept a string type, is there another option to query a custom OID?

An on-host script periodically checks RAID status (requires root, executed via cron) and dumps the required text output into a chmod 444 file that snmpd can read. This file is then snmp extend ingested into an OID, something like;

extend . raid '/bin/cat /tmp/raid-status

If all is well then an “Opt” value (Optimal, any other state will be investigated) is present in that string line, if not then alert

0 PERCH330Adapter 8 2 1 0 1 0 Msng On 3 N 0 Opt

As per title, Custom OID is not suitable, can’t seem to find a suitable Nagios plugin, so any suggestions please on how I could monitor and display/alert on this OID and value?

Capture Debug SNMP shows that the OID is being populated:

. = STRING: " 0 PERCH330Adapter 8 2 1 0 1 0 Msng On 3 N 0 Opt "

Probably add an application:

I did think if that but couldn’t find any docs on adding a new application? The docs I could find referenced using existing application, not creating new ones, any guidance please?

Sorted it in the end, used a Service check (Nagios check_snmp) and suitable regexp to flag on anything other than expected.

-o -P 3 -L authPriv -U [username] -a SHA -A [auth-pass] -x AES -X [crypt-pass] -r '\bOpt\b'

I was caught out templorarily by the Nagios services plugins inheriting -H host but not the stored device creds.