Updating Fedora with Read-Only Root Filesystem

When using dnf system-update on a Fedora machine that has a read-only root filesystem, it is important to make sure that the filesystem will be mounted read-write automatically first. Edit /etc/fstab and change it to rw before rebooting, lest the update will fail.

I imagine the offline update process really should remount the root filesystem on its own, but that does not appear the case, at least for now.