[arch-dev-public] network interface naming with systemd 197

[Dave Reisner]

Just an FYI:

Upstream pushed a commit[0] which gives network devices persistent, and
unique, names based on hardware attributes, avoiding the random kernel
names. While this solves a real problem, it's also a fairly jarring
change. For example:

$ udevadm info /sys/class/net/eth0
P: /devices/pci0000:00/0000:00:1c.2/0000:05:00.0/net/eth0
E: DEVPATH=/devices/pci0000:00/0000:00:1c.2/0000:05:00.0/net/eth0
E: ID_BUS=pci
E: ID_MODEL_ID=0x4364
E: ID_NET_NAME_MAC=enxbcaec50bfcc8
E: ID_NET_NAME_PATH=enp5s0
E: ID_OUI_FROM_DATABASE=ASUSTek COMPUTER INC.
E: ID_PCI_CLASS_FROM_DATABASE=Network controller
E: ID_PCI_SUBCLASS_FROM_DATABASE=Ethernet controller
E: ID_PRODUCT_FROM_DATABASE=88E8056 PCI-E Gigabit Ethernet Controller
E: ID_VENDOR_FROM_DATABASE=Marvell Technology Group Ltd.
E: ID_VENDOR_ID=0x11ab
E: IFINDEX=2
E: INTERFACE=eth0
E: SUBSYSTEM=net
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/eth0
E: TAGS=:systemd:
E: USEC_INITIALIZED=42063

If I were to reboot right now (systemd-git), eth0 would become enp5s0. I
tend to think that this is fairly extreme, and would throw off a lot of
people -- especially those who never needed to deal with interface
renaming.

For systemd 197, I plan on shipping this rule as documentation in
/usr/share/doc/systemd and _not_ enabling it by default. Those who want
to opt in can simply copy the rule to /etc/udev/rules.d. They can also,
of course, continue to use whatever MAC-based rules they might have, but
I would strongly recommend switching these rules to be triggered by
ID_NET_NAME_{SLOT,PATH,ONBOARD} instead.

Cheers,
Dave

[0] http://cgit.freedesktop.org/systemd/systemd/commit/?id=394e2938ff9