metlog-psutils is a plugin extension for Metlog <http://github.com/mozilla-services/metlog-py>. metlog-psutils provides details about network connections, memory usage, cpu usage and even some thread details.
This plugin works best on Linux. Running the plugin under OSX will skip some functionality and will require root privileges.
More information about how Mozilla Services is using Metlog (including what is being used for a router and what endpoints are in use / planning to be used) can be found on the relevant spec page.