Diamond is a python daemon that collects system metrics and publishes them to Graphite. It is capable of collecting cpu, memory, network, i/o, load and disk metrics. Additionally, it features an API for implementing custom collectors for gathering metrics from almost any source.
The documentation can be found on our wiki. For your convenience the wiki is setup as a submodule of this checkout. You can get it via running
git submodule init
git submodule update