[collectd] customizing metrics paths for various plugins

[Florin Andrei]

New to this project, I am testing collectd as a metrics collector to be 
used with Graphite. Everything's fine so far, and I am very impressed 
with how easy it is to collect high-frequency samples with very low CPU 
usage.

I've enabled the CPU plugin and the metrics are showing up in Graphite. 
But each individual metric is prefixed with "cpu-":

collectdlocalhostcollectd/
├── cpu-0
│   ├── cpu-idle.wsp
│   ├── cpu-interrupt.wsp
│   ├── cpu-nice.wsp
│   ├── cpu-softirq.wsp
│   ├── cpu-steal.wsp
│   ├── cpu-system.wsp
│   ├── cpu-user.wsp
│   └── cpu-wait.wsp

This seems redundant, and when visualized with Grafana, it takes too 
much space in the legend. Is there a way to get rid of the "cpu-" prefix 
in the metrics names? Let's say for the user metric, I want the path to 
be...

host.cpu-0.user

...instead of...

host.cpu-0.cpu-user

Same question for the memory plugin.

For the load plugin, the path is load.load.longterm - here the load 
label appears on two different levels. Can I get rid of one level?

Also, is there a way to group some plugins under the same branch? I'd 
like CPU, memory, load, etc to fall under the category "os". Other 
plugins, such as Apache, etc. I'd like to group under the "app" 
category.

host
   os
     cpu
     memory
     load
   app
     apache

It's not clear to me how to manipulate these paths with collectd.

-- 
Florin Andrei
http://florin.myip.org/