As usual, every time I upgrade Fedora I write a blog post to preserve this knowledge for others who might run across the same problem or in case it happens to me again next year.  This time around the situation was a little less smooth than previous upgrades.  After the preupgrade was done, when I rebooted I was 2 MB short in /boot.  This shouldn’t happen to you if you started with Fedora recently, but I’ve been on the same install for two years.  In the past if the preupgrade failed, the installer would put your system back into its previous configuration and you could use it again.  This time around it didn’t do that and I no longer had a working system.  It complained that a bunch of services weren’t starting and I couldn’t get a shell, not even in single user mode.