Munin: LWP::UserAgent and Cache::Cache

Every time I install Munin (which happens rarely, so I forget everything) I end up figuring out why there is no data from MySQL and Nginx. The causes are these: the Nginx plugin reports LWP::UserAgent not found, and the MySQL plugin complains about Missing dependency Cache::Cache. Both messages subtly hint at missing Perl libraries.

Fixing the dependencies:

• “LWP::UserAgent not found”: apt-get install libwww-perl
• “Missing dependency Cache::Cache”: apt-get install libcache-cache-perl

If you install these libraries before installing Munin, you won’t have to fiddle with munin-node-configure afterwards. That is, provided you already have Nginx status set up, i.e. your Nginx config has something like this:

server {
        listen 127.0.0.1:80;
        server_name localhost;

        location /nginx_status {
                stub_status     on;
                access_log      off;
                allow           127.0.0.1;
                deny            all;
        }
}

I hope this post saves time not only for me next time :)