[$] Systemd catches up with bind events

The kernel project has a strong focus on not breaking user-spaceapplications; if something works with a given kernel release, it shouldcontinue to work with subsequent releases. So it may be discouraging toread the lengthy exposition on an apparent user-space API break in the announcement for the systemd 247-rc2release. Changes to udev configuration files will be needed to keepsystems working, but thesystemd project claims that it "is not [the] fault of systemd or udev, butcaused by an incompatible kernel change that happened back in Linux4.12". It seems like an appropriate time to look at what happened,how administrators need to respond, and whether anything can be done toavoid this kind of thing from happening again.