OpenNMS Horizon with RRDtool

As described in the previous article we have built and installed an OpenNMS Horizon Core component from the source. It comes with a Java implementation of RRDTool called JRobin. The portability of Java applications allowed users to run OpenNMS platforms where RRDTool wasn’t easily available. It was threadsafe and allowed more threads writing data. RRDTool implemented that functionality and surpassed JRobin performance and feature wise.

💁‍♀️ If you just don’t care in a dev or testing environment, you can use JRobin for simplicity, because it’s just there and works out of the box. For any production environment, I highly recommend to use RRDTool. It gives you much better support for tools, performance and features. Migrating later is doable but painful.

RRDtool graph improvement

If you have OpenNMS with RRDtool running, you can improve the whole rendering a little bit just by replacing the command.prefix in the following files:

• snmp-graph.properties
• snmp-adhoc-graph.properties
• response-graph.properties
• response-adhoc-graph.properties

command.prefix=/usr/bin/rrdtool graph - --imgformat PNG --font DEFAULT:7 --font TITLE:10 --start {startTime} --end {endTime} -E --width=1000 --height=180

I don’t like the stamp size graphs in OpenNMS, so I changed it for all. It could be problematic if you have grouped graph report (KSC report). So if you have trouble, you can just remove the –width and –height parameter. The command will also overwrite the width and height for all graphs, so they have all the same size. You have to be careful if you have KSC reports with multiple columns. If you have RRDtool running, you can improve the graphs with anti-aliasing using a few additional parameters: