Re: [gentoo-user] Re: udev upgrade renames eth-interfaces

[Dan Johansson]

On Saturday 16 March 2013 12.08:23 Canek Peláez Valdés wrote:
> On Sat, Mar 16, 2013 at 11:03 AM, Dan Johansson <Dan.Johansson@×××.nu> wrote:
> > On Saturday 16 March 2013 09.39:17 Jonathan Callen wrote:
> >> > Hello,
> >> >
> >> > Today I upgraded udev on one of my boxes (after hesitating a long
> >> > time). Even if  I have /etc/udev/rules.d/80-net-name-slot.rules and
> >> > my old 70-persistent-net.rules in place, my interfaces gets renamed
> >> > (eth0 gets swapped with eth1) which then messes up my whole
> >> > configuration (routing tables and firewall rules). Any suggestion
> >> > how to keep my old names and order?
> >> Udev, as of version 187, will now refuse to rename a network interface
> >> to the name of a network interface that already exists -- which, due
> >> to race conditions, can be the case if you are attempting to rename a
> >> network device to a name the kernel will later use to name the next
> >> enumerated device.  The fix for this issue is to *not* use names that
> >> match "eth[0-9]*", "wlan[0-9]*", etc. and instead use a name that the
> >> kernel would *not* automatically assign.  Unfortunately, that means
> >> that you *cannot* keep your old names and order (upstream claims that
> >> the means used to ensure those names were used was unreliable and
> >> prone to race conditions anyway, which, looking at the code, I can
> >> believe).
> > This is great...
> > (I hope you can hear the irony)
> >
> > OK, so I removed the two udev rules (70-persistent-net and 80-net-name-slot) files, thinking if this is the way the "upstream devs" are going then I have to check it out.
>
> That's the smart thing to do.
>
> > After removing the udev-rules and rebooting I got my two new network interfaces called enp0s4 and enp0s5 (no idea what that is supposed to mean).
>
> http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
>
> http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c
>
> Basically, "en" is for "ethernet", "p" is for "PCI bus", and "0s4" and
> "0s5" is for the topology of the cards in your machine: the cards are
> in the PCI bus number 0, slot number 4 and 5. In other words, if you
> do "find /sys -name enp0s4", I'm betting you will get something like:
>
> /sys/devices/pci0000:00/0000:00:1c.1/0000:00:004.0/net/enp0s4
>
> The "0000:00:004.0" is the part that determines the naming of yout
> device. This naming is deterministic: as long as you don't move the
> cards from PCI slot, they will be named like that always.
>
> > My next step was to replace eth0 with enp0s5 and eth1 with enp0s4 in /etc/conf.d(net and create two new links (net.lo -> net.enp0s[45]) in /etc/init.d
> > Now I could start the two network interfaces (/etc/init.d/net.enp0s[45] start).
> > BUT, as soon as I try to start  some service (sshd, ntpd, ...) that is using the network I get a lot of complains that eth0 and eth1 is not started (and can not be started) and the service wont start.
> > What have I missed???
>
> Do you have net.eth0 or net.eth1 in /etc/rc.conf?

No, but I still had the links in /etc/init.d/. Removing those and adding lins for enp0s[45] did the trick.

Thanks,
-- 
Dan Johansson, <http://www.dmj.nu>
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