This is confirmed as a systemd-udev regression.
Code that previously existed in rename_netif() to support a temporary interface name ("rename%u") has been removed. As a result, the '70-persistent-net.rules' actions that try to shuffle existing names will now fail.
systemd commit log:
commit 97595710b77aa162ca5e20da57d0a1ed7355eaad Author: Kay Sievers <email address hidden> Date: Thu Jul 5 17:40:50 2012 +0200
udev: network device renaming - immediately give up if the target name isn't available
This is confirmed as a systemd-udev regression.
Code that previously existed in rename_netif() to support a temporary interface name ("rename%u") has been removed. As a result, the '70-persistent- net.rules' actions that try to shuffle existing names will now fail.
systemd commit log:
commit 97595710b77aa16 2ca5e20da57d0a1 ed7355eaad
Author: Kay Sievers <email address hidden>
Date: Thu Jul 5 17:40:50 2012 +0200
udev: network device renaming - immediately give up if the target name isn't available