So, I was playing a bit with Munin and I wanted to monitor a simple Apache2 webserver. For some reason, the Apache stats did not show up even tough my configuration was 100% correct:
The plugins were enabled using:
ln -s /usr/share/munin/plugins/apache* /etc/munin/plugins/
The /etc/munin/plugin-conf.d/munin-node configuration file contained
[apache*] env.ports 80
The Apache mod_status plugin was enabled and the ExtendedStatus property was set to On.
But still no graphs in Munin.
Running /etc/munin/plugins/apache_processes autconf should give you a clue: no (LWP::UserAgent not found) (it is supposed to say yes 😉 )
The same error message shows up in the output of munin-node-configure –suggest
Plugin | Used | Suggestions ------ ... apache_accesses | no | [LWP::UserAgent not found] apache_processes | no | [LWP::UserAgent not found] apache_volume | no | [LWP::UserAgent not found] ...
I had no idea what this LWP::UserAgent thing was untill I searched outside the Munin context and found out it was a Perl library which you can install under Debian by invoking
sudo aptitude install libparse-http-useragent-perl