What is broken with software update?

[John Mellor]

On Sun, 2015-09-13 at 18:36 -0700, Gordon Messmer wrote:
> On 09/13/2015 07:07 AM, John Mellor wrote:
> > Then (since I'm developing a deep distrust of software update), I
> > did a
> > CLI dnf update.  There were 27 updates pending.  Clearly, software
> > update is broken.
> 
> Nothing is clearly broken.
> 
> yum/dnf repositories are not synchronized.  No mechanism nor mandate 
> exists for keeping them in sync.  This has been discussed to death on
> this list, but no example has been provided that can't be explained 
> simply as "dnf checked a repository with older data and then, later, 
> checked a different repository with data that is more up to date."
> 
> That's the way distributed mirror systems work, and it's nothing to 
> worry about.  You *will* get updates, when the mirrors pull data.
> 
> If you're concerned about getting updates immediately, don't rely on
> dnf 
> at all.  Subscribe to the RSS feed:
> http://fedoraplanet.org/infofeed/
> 
> There's a perfectly good, centralized source of information about 
> updates available to everyone.

Gordon stated:
> Nothing is clearly broken.

Ok, its remotely possible.  My recalled experience has been that the
Gnome updater is not finding even 5-day-old updates, but assuming that
some weird preferred repo out there is totally broken, I'm willing to
test that thesis.

I checked the dnf log and dnf is configured to select some
indeterminate Fedora mirrors site.  I'm willing to bet that the
unselected mirrors are no more than a couple of hours out-of-date at
worst, and there is actually a software error at work here.  So, how to
I preconfigure my system to get the two updaters to select the same
repo?

P.S, just out of curiosity, why is the software updater not sharing the
same dnf and yum metadata backend that clearly works better?