Issue I often want to review important aspects of nodes in OpenNMS including: SNMP status, services, IP addresses, group membership, data links, and critical path settings. The OpenNMS interface does not provide an easy way to quickly review these items in bulk. Some of this information can be viewed on the OpenNMS node page but a list [...]
Issue The OpenNMS poller-configuration.xml file controls what services are monitored. Fine grain exceptions to the poller-configuration.xml can be created using the OpenNMS web interface: node admin page -> Manage and Unmanage Interfaces and Services. This allows monitoring of a service or an entire interface to be turned off when the poller-configuration.xml would normally cause it to be [...]
Issue OpenNMS stores name information from several sources in its database but only makes some of it available in the web interface. It’s useful to see all this information in one place for auditing and searching. It’s also important to check which name (Manually set by administrator, DNS, NetBIOS (SMB), SNMP, or lowest numbered IP) OpenNMS has chosen for [...]
Issue OpenNMS stores DNS reverse lookups for the IP addresses it discovers (iphostname column of the ipInterface table). It appears that OpenNMS only performs the DNS reverse lookup once and stores the result. Therefore, OpenNMS may never be aware of a DNS change. The DNS reverse lookup is visible in the OpenNMS web interface on the node page as “IP [...]
Issue As with any large system, statistics are a useful management tool. OpenNMS gives the number of nodes at the bottom of the Node List page but few other statistics are available. In particular, knowing how many interfaces and services have been discovered and are monitored would be useful. The number of active jrb files [...]
Issue If you’ve ever had a router go down and been flooded by outage notifications for devices behind the router then you probably looked into using OpenNMS’s critical path outage feature. Critical path outages stop notifications about a node if another IP address is also not available. If properly configured, a router failure will only [...]
Issue OpenNMS supports more than one node having the same IP address. This is required in many high availability configurations so it’s not unexpected that OpenNMS allows it. However, erroneous duplicate IP addresses on the same network is a common configuration problem that is often hard to identify. Besides real cases of duplicate IP addresses [...]
Issue OpenNMS captures the SNMP Description field which is a useful source of information, often containing device patch levels, vendor, etc. Searching for nodes based on their description or simply seeing a list of all the descriptions can be useful. OpenNMS does not directly provide a feature for this.
Most of the scripts on this site output HTML so it’s easier to run them from a web server than on the command line. The following configuration is needed to serve the scripts through an Apache 2 web server. The configuration below does the following: Proxies the OpenNMS web interface through Apache. Provides a document [...]
Issue Managing jrb files is an important factor in large OpenNMS deployments. OpenNMS can collect a tremendous number of jrb files which contain SNMP and response data. SNMP jrb files are created as a result of alias definitions in $OPENNMSBASE/etc/datacollection-config.xml and response jrb files as a result of ds-name definitions in $OPENNMSBASE/etc/poller-configuration.xml. It’s useful to know how much [...]