On Fri, Sep 01, 2023 at 08:40:43PM -0500, David Wright wrote: > I know you have a low opinion of allow-hotplug, but I can't see that > auto/allow-auto is necessarily better for the naive user that doesn't > install a DE for whatever reason. > > AIUI auto gives you a one-shot attempt to start the network at boot > time, and if that fails for any reason (eg USB not yet plugged in/ > not detected/hardblocked on/etc), you get a long timeout before the > login prompt, and may have to reboot to get it to attempt again. > > OTOH allow-hotplug gets you to a login prompt as normal, without the > network being up, and then rectifying the problem makes ifupdown/udev > automatically have another go.
It depends on the hardware, and how the system is going to be used. A built-in ethernet interface SHOULD NOT be configured as "allow-hotplug". It should be "auto". I'd argue that the same applies to a PCI card or other non-built-in but internal device. If you have to take the machine apart to remove the device, it's "auto". allow-hotplug is intended for things like USB ethernet interfaces, as you mention. They're literally hot-pluggable, and may not be present when the system is booted. If you're dealing with one of those, then by all means, use allow-hotplug for it. That's what it's for. My gripe is that the installer has (traditionally?) used allow-hotplug for ALL ethernet interfaces, including the built-in interfaces on a server. This causes massive problems with the ordering of service initializations at boot. It took me a *long* time and a lot of digging to figure out why things were breaking, so I try to pass that knowledge along for others.
