Zincati provides Prometheus metrics via a Unix socket. In order for
these to be scraped by `vmagent`, they need to be exposed over HTTP.
The `local_exporter` is designed to do specifically this.
Unfortunately, the Zincati metrics socket is only accessible by the
*zincati* user, so the `local_exporter` also needs to run as that user.
Hopefully, the user ID will remain consistent in future versions of
CoreOS.
Dustin