[arch-projects] [udev][RFC][3/5] deprecate persistent-{net-cd}.rules

[Tom Gundersen]

I'd like to remove the following deprecated functionality from initscripts/udev.

The issue:

If you have several networking devices or cd-rom's they might get
their names swapped around on reboot. This is of course annoying.


The old solution:

udev ships with a rule file to automatically generate a persistent
rule file in /etc every time it sees a new network device or cd-rom.


The problems:

/etc might not always be writable (in particular it is not during
early boot when devices are typically probed), for this we have a
workaround/hack in initscripts that will copy temporarily stored rule
files to /etc when /etc becomes available.

these days things like usb modems pretend to be cdroms so one might
have potentially a lot of nonsense rules generated

the functionality is basically deprecated upstream, i.e., they intend
to rip it out as soon as someone has written a nice tool to replace
it. For all intents and purposes it is dead.


The correct solution:

The user should not enable the auto generation rules, but rather
create his/her own rules in the cases where they really want it. This
is the same amount of manual intervention as enabling the rules, with
none of the drawback. The correct procedure is excellently described
here: <https://wiki.archlinux.org/index.php/Udev#Mixed_Up_Devices.2C_Sound.2FNetwork_Cards_Changing_Order_Each_Boot>
(the method referred to as the "udev-sanctioned" one).


The situation in Arch:

The auto generation rules are shipped, but patched to be disabled by
default, the needed support is still in initscripts.


My suggestion:

We announce the deprecation and point users to the correct solution
(maybe we fix up the relevant wiki pages a bit). After a not too long
time we stop shipping the autogeneration rules, i.e., we pass

--disable-rule_generator

to configure in the udev package, and remove the support from initscripts.


What this will mean for the end user:

On an existing system where the rules are enabled and no new devices
are added: nothing.

On an existing system where the rules are enabled and a new device is
added: the new devices will not get an auto generated persistent rule
and an error will be logged.



Thoughts?

Cheers,

Tom