Robin Bowes

OpenNMS ships with the thresholds for some events already defined. For example, there is a memory threshold defined as: <group name="netsnmp-memory-nonlinux" rrdRepository="/opt/opennms/share/rrd/snmp/"> <expression type="low" expression="memAvailReal / memTotalReal * 100.0" ds-type="node" ds-label="" value="5.0" rearm="10.0" trigger="2"/></group> ie. if free memory drops below 5% then an event will be created. The alert will be cancelled automatically if free memory subsequently rises above 10% I wanted to configure some specific nodes with a different threshold, eg. generate an event when free memory drops below 2.5%. Here's what I did.

I had a utility server running RHEL 6.2 (I installed it as part of a RHEV evaluation process). However, I have no RHEL entitlements so am not able to get updates. So, I converted it to CentOS 6.2, with a little help from this post : yum clean all mkdir ~/centos cd ~/centos wget http://mirror.centos.org/centos/6.2/os/x86_64/RPM-GPG-KEY-CentOS-6 wget http://mirror.centos.org/centos/6.2/os/x86_64/Packages/centos-release-6-2.el6.centos.7.x86_64.rpm wget http://mirror.centos.org/centos/6.2/os/x86_64/Packages/yum-3.2.29-22.el6.centos.noarch.rpm wget http://mirror.centos.org/centos/6.2/os/x86_64/Packages/yum-utils-1.1.30-10.el6.noarch.rpm wget http://mirror.centos.org/centos/6.2/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.30-10.el6.noarch.rpm rpm --import RPM-GPG-KEY-CentOS-6 rpm -e --nodeps redhat-release-server rpm -e yum-rhn-plugin rhn-check rhnsd rhn-setup rpm -Uhv --force *.rpm yum upgrade reboot Nice!