Monitoring Your SNMP Script with Mon

Now let's monitor this SNMP MIB with another SNMP monitoring script called netsnmp-exec.monitor. Copy this script from the chapter17 directory on the CD-ROM into the /usr/lib/mon/mon.d directory, and set the permissions of the file so Mon can execute it:

 #cp /mnt/CDROM/chapter17/netsnmp-exec.monitor /usr/lib/mon/mon.d #chmod 755 /usr/lib/mon/mon.d/netsnmp-exec.monitor 

Create a mon.cf service entry (underneath the existing watch clusternodes entry) that looks like this:

   service custom-snmp-monitor-script     description Checks the output of the custom SNMP script     interval 5s     monitor netsnmp-exec.monitor     depend clusternodes:ping     period wd {Su-Sa}       alert mail.alert [e-mail]       upalert mail.alert [e-mail] 

(Of course, you would normally install this script on all of the cluster nodes and modify the /etc/snmp/snmpd.conf file on all of the cluster nodes.)

You can test this Mon configuration (once you've restarted Mon) by modifying the check-dns script again and changing the host to a bogus host. This should cause Mon to raise the alert you have specified (Mon will send an email to [e-mail] in this example).

You can have multiple custom monitoring scripts. Each additional script can be monitored individually with the netsnmp-exec.monitor script by passing it the -n argument followed by a number to represent which script to use from the snmpd.conf file. The default, if the -n argument is not used, is to check all scripts.

Note 

You may also want to use the -t 10000 argument to specify a timeout value for the netsnmp-exec.monitor script in your mon.cf entry.