4 ms·

Your hardware is reporting that peripherals have logically moved, so yeah, the names change? It's definitely not perfect, but also consider that this is in part

Your hardware is reporting that peripherals have logically moved, so yeah, the names change? It's definitely not perfect, but also consider that this is in part to help manage larger fleets of systems, and if you have thirty of the same machine and you put thirty add-in PCIe ethernet cards into them, at least they'll all predictably change and so in your test lab (you got a test lab for this hypothetical fleet, right?) you'll know what your changes are causing and be able to roll out synchronized software changes to pick up on it. We don't all have fleets of machines, of course, and systemd has functionality for disambiguation in a single-system environment where interfaces might appear and disappear sometimes. udev also has a mode where the interface is automatically named after its MAC rather than its physical location. It's not on by default on any Linux distro I know of, but it's just a flag IIRC.

ricktdotorg 5y ago
really good, measured & insightful replies. thank you!
jeffbee 5y ago
I just went through a lengthy diagnosis of systems that weren't optimal because something in systemd was trying to match devices prefixed by "pci/" and udev formats the device path as "pci-" so I am kinda not ready to talk about my trauma yet.
- ethbr0 5y ago
  "Well there's your problem right there. Some damn fool over rotated your trailing character by 45°!"
immibis 5y ago
Being hardware or software makes no difference: the fact is that network adapters still change names, but now you can't assume the default is eth0 on most systems.
- eropple 5y ago
  The idea of a "default" interface for a particular physical transport is worth examining for coherency, I think. If you only have one adapter, then it's the one that shows up when you list your interfaces, so script to that end. If you have more than one, then trusting an ordering that can change on boot is unsafe. But don't worry - those of such a soberly considered persuasion can just use the configuration management they've definitely built and that necessitates such assumptions as "there's always an eth0" to bring it back.

ricktdotorg 5y ago

really good, measured & insightful replies. thank you!

jeffbee 5y ago

I just went through a lengthy diagnosis of systems that weren't optimal because something in systemd was trying to match devices prefixed by "pci/" and udev formats the device path as "pci-" so I am kinda not ready to talk about my trauma yet.

ethbr0 5y ago
"Well there's your problem right there. Some damn fool over rotated your trailing character by 45°!"

immibis 5y ago

Being hardware or software makes no difference: the fact is that network adapters still change names, but now you can't assume the default is eth0 on most systems.

eropple 5y ago
The idea of a "default" interface for a particular physical transport is worth examining for coherency, I think. If you only have one adapter, then it's the one that shows up when you list your interfaces, so script to that end. If you have more than one, then trusting an ordering that can change on boot is unsafe. But don't worry - those of such a soberly considered persuasion can just use the configuration management they've definitely built and that necessitates such assumptions as "there's always an eth0" to bring it back.