Main config only servers either a. DNS round robin or b. static config on the client (in case of main DNS failure).
These config servers use a geography/topography to mirror database and return the URL of a mirror or mirrors to use for this update only.
The client can cache/remember the last working mirror or mirrors in case of config server failure.
cache where?
Although I don't think we have to build a failsafe system, it is good to be able to dynamically change the mirrors without having to modify the client config, but at the same time, give the client enough power to pick a mirror if they want.
Much of this could all be hidden behind an http server as long as yum supports following redirects.
It does.
(apologies for not posing this thread to centos-devel, I was sending out errata messages at the time and was not thinking).
So am I to assume you'll be writing this code. :)
-sv