(To possibly help with the agenda): I'm not really happy about changing the user's environment in an incompatible way, and the rationale seems to be "it is easier to implement this way"[1], which is rather weak.

Perhaps worth putting on the agenda just to make sure there are no better options available?

[1] Or is this simplifying too much?

Quoting Lennart Poettering:

Or in other words, we'd like one of three answers from FESCO: a) feature
declined, b) feature accepted but leave the new logic off on upgrades,
c) feature accepted but enable it on upgrades too.

Replying to [comment:1 mitr]:

the rationale seems to be "it is easier to implement this way"

Is this how you read these emails from Kay?:

https://lists.fedoraproject.org/pipermail/devel/2013-January/176762.html

https://lists.fedoraproject.org/pipermail/devel/2013-January/176773.html

Replying to [comment:3 michich]:

Replying to [comment:1 mitr]:

the rationale seems to be "it is easier to implement this way"

Is this how you read these emails from Kay?:
Yes.

https://lists.fedoraproject.org/pipermail/devel/2013-January/176762.html
[biosdevname implemented something...]
udev intentionally '''wants''' to be dumb and strictly prefers device-local views,
(emphasis mine)

https://lists.fedoraproject.org/pipermail/devel/2013-January/176773.html

Udev provides exactly the same without the "guessing" part.

IOW, it is perfectly possible to do exactly what biosdevname did (after all, it was possible to simply invoke biosdevname), but implementation concerns make that unattractive.

AGREED: systemd/udev Predictable Network Interface Names are accepted as F19 feature (+7,-0)

AGREED: systemd/udev Predictable Network Interface Names - upgrades shouldn't change naming (+5,-0)

AGREED: eno=>em tweak is required (+5, -1)

I don't know if it's significant enough for FESCo to care, but I figured it'd be worth noting somewhere (as well as https://bugzilla.redhat.com/show_bug.cgi?id=965718 ) that this feature has not yet been implemented as planned, either in F19 or F20.

As per that bug report, in F19, you got a mess: https://bugzilla.redhat.com/show_bug.cgi?id=965718#c9 sums it up possibly the best. In F20, it seems like we fairly consistently have biosdevname names used, by default, everywhere; if you pass 'biosdevname=0' to the installer you should get systemd names used. But biosdevname is still the default, not this feature.