No, rrd4j is embedded (at least it was for OH 1) requiring no additional installation. What didn’t work?
NOTE: There are limitations with rrd4j including: can only save numbers, usually only works when you save values at least once per minute.
I’m no expert on OH 2 yet. My understanding though is that the config files have been broken out into separate files so I would expect you would either configure it through PaperUI or through a file named something like mqtt.conf.
Unfortunately, the “Installing an Extension” part of the tutorial is not yet written. But this post should be helpful: