Creating icons for Nagios
March 30th, 2010 | by jim |By default, the statusmap of Nagios does not include any useful icons for your equipment. There are some icon collections on http://www.monitoringexchange.org/, and a handy set can be installed with the nagios-images package.
However, there will come a time when you want your own customised icons, and information on how to produce them is hard to come by. The status map is assembled as nagios starts with the GD library, and therefore the recommended format for icons is .gd2, but strictly speaking that’s an intermediate format and most tools don’t give you any options to create them.
Start by creating an SVG files in Inkscape. Make the icon around 40×40 pixels; this small size won’t matter at all while editing in Inkscape, as vectors scale very well! Avoid using black — the next steps in the toolchain will treat black as transparent. Instead use a blackish colour, such as #010101.
Just before saving the file, go to “Document Properties” and set the page size to fit the selected icon.
When the SVG file is ready, save it. We’re finished with Inkscape now, and now we drop to the command-line to use rsvg-convert from the librsvg2-bin package. By default this will create a PNG file, which we can use as the Nagios icon_image. Then we use netpbm tools to grab the transparent part of the PNG, and write out a GD2 image
$ rsvg-convert example.svg > example.png
$ pngtopnm example.png | pnmtopng -transparent =rgb:00/00/00 2>/dev/null | pngtogd2 /proc/self/fd/0 example.gd2 0 1
The pngtogd2 command comes from libgd-tools, and is slightly annoying in that it won’t take STDIN … so we fake it using /proc/self/fd/0. The “0 1″ parameters set the chunk size and format, and are cargo-culted from the web and Nagios documentation. The black areas in the PNG are marked in GD2 as being transparent.
So now you can create nice Nagios icons easily. I’ll be publishing a set of basic icons and their source SVG files on code.inode.co.nz soon.
Tags: nagios