Identify NICs by MAC-addr, not ifName.
An idea is to identify NICs by MAC-address, not interface names. I've seen numerous situations where ifNames were NOT stable, even though we now have the nice 'enp3s31f6'-ifNames that should be stable.
Some server hardware 'intelligently' reconfigures PCI-lanes(?) based on the number of cards inserted.
Rationale: MAC-addresses are always stable. No matter where a NIC is inserted.
It does pose problems when replacing 'eth0' because 'eth0' was broken. The new 'eth0' will not configure because its MAC-address changed...