Hello. On Thu, Jan 07, 2016 at 02:47:31AM +0000, Ben Hutchings wrote: [...] > The real problem is that vconfig (or rather the kernel interface it > used) imposed any scheme at all. Requiring a '.' is equally short- > sighted. Let me give an example:
IMHO not equally, but yes... too shortsighted. [...] > But instead of letting the names depend on the underlying hardware > configuration, some time ago I started naming them 'ext0' (modem) and > 'wl0' (wireless AP) and it's pretty clear which of this is which. When > I changed the hardware and added VLANs there was very little need to > change configuration outside of /etc/network/interfaces. Seems like we're wandering into discussing best-practises and let me share my view for the potential benefit of mailing list readers... Obviously the below applies only to a "managed server", not to something which is basically unmanaged/autoconfigured/zeroconf system (like a roaming laptop or some embedded device). I fully agree with giving meaningful "functional" names to your interfaces. These should NOT be based on what hardware is used, protocol types, vlan, tunneled, or anything like that but instead on what they're used for, eg. wan, lan, dmz, ... (or if you prefer: ext, int, ...) (IMHO it's good to avoid numbers completely in these names, eg. if you provide separation of your internal network in zones with different "trust level" instead of int0 and int1, use eg. intwired and intwlan or whatever your separation/trust-level is based on.) Using functional names (hopefully/likely) means you've set up a reliable way to get the same interface named and you're not subject to hardware ordering, initialization ordering, someone enabling "predicable interface naming" schemes, etc. It also provides a good abstraction. - your firewall rules will be more functional and easier to read when you set them up as "... -i wan -o lan ..." rather than relying on some hardware name. - if you're ISP fscks their routing or similar partial outtakes you can simply set up a tunnel to somewhere, temporarily take down your "real" wan and name the tunnel wan and everything else on your system should be ready to go.... This has proven really useful when you provide a somewhat critical service in my experience. - ... many other reasons, zero cost abstractions are really useful. Let me also state that even if you can enable predictable interface naming using systemd, or whatever, these names are still not functional so you've still failed to follow best practises if you rely on them. (Let alone if you think eth* names are reliable you're simply wrong.) Following these best-practises means the discussions about if systemd enables predictable interface naming scheme or not is (for people managing servers) completely uninteresting. You'll simply treat anything which does not have a functional name as if it's an unused spare. You give it a functional name /before/ even considering bringing UP the interface. (I hope it's also obvious that in any zeroconf situation it's useful that an interface gets the same (initially random as far as I'm concerned) for each consecutive boot. But for your managed server usecase, this is completely uninteresting.) Regards, Andreas Henriksson
