Re: [gentoo-user] from Firefox52: NO pure ALSA?, WAS: Firefox 49.0 & Youtube... Audio: No

[Neil Bothwick <neil@digimed.co.uk>]

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On Thu, 22 Dec 2016 04:15:50 +0100, lee wrote:

> > There are no config files to edit with the predictable names, the
> > names are created from the physical location of the port.  That's why
> > they are called predictable,  
> 
> I only know what the names are when I can look them up when the computer
> is running.  I don't call that "predictable".

If they are constructed according to specific rules, they are
predictable, by definition.

> They were much more predictable before because I could be reasonably
> sure that each of the ports would be called 'ethN', starting with N = 0,
"Reasonably sure" is not predictable. A lot of this stuff is designed to
make automated management easier, so editing rules or config files is
undesirable. It is more about being able to automatically provision and
configure new systems, whether hardware or virtual.

> unless I changed a card for a different one after an udev rule had
> already been created.

and being able to make changes without messing with the rest of your
system. I stand by my previous analogy of disk devices nodes vs UUIDs.
One is readable the other is safe. Yes, you can use filesystem labels,
which can be both, but that requires intervention, just like your udev
rules. That doesn't make either approach wrong, just suited to different
purposes.

> > unless you move the NIC to a different PCI slot, it will always have
> > the same name, no matter what other hardware you add or remove. Yes,
> > the names are cumbersome, but they have to be like that to guarantee
> > their uniqueness.  
> 
> You don't need to defend the unrecognisable names.  The names used for
> referring to network ports don't need to be like that.

No they don't. It is merely one solution to the problem, and the names
are recognisable, Alan posted the key earlier. They are complex and may
look cryptic until you understand them, but so is English.
 
> The perceived advantage lies in being able to refer to network ports in
> a more reliable way, and I don't see how using unrecognisable names
> instead of recognisable ones would make anything easier.

See above re automation. It doesn't really matter whether you see the
need or not. If you don't have the need, don't use it, they are an
option for those who do want them.
 
> It would have made things easier if the problem had been solved by
> giving them recognisable names (or aliases) by default --- or even if
> the default names (aliases) were the same as the unrecognisable names
> --- and allowing to easily configure the names (aliases) actually used
> to refer to the ports.

That's a good point, and surely doable with udev rules, making the whole
argument moot. I haven't investigated because I don't have the need, but
I would be interested to hear what you discover.
 and not that unrecognisable once you understand the systax.

> Being able to refer to things in more reliable ways improves the quality
> of the software.  Using unrecognisable names for things reduces the
> quality.

They are reliable, unlike your "reasonably sure" approach, 


> This is like you're defending a type of new pliers.

I'm not so much defending them and expressing an opinion. I can see the
benefits and the drawbacks. They are an option, albeit one that is turned
on by default (but since when have Gentoo users ever been bothered about
upstream defaults?). Portage even gives you explicit instuctions on how
to permanently disable them with a single command, although I generally
use the net.ifnames=0 kernel option instead on single NIC machines, where
the feature is pointless.

> But who knows, perhaps it is now possible to easily, on the fly, name
> the network ports through a neat configuration file.  I'm merely asking
> if there is because I don't know and would find that very useful.

Can't ifrename do what you want?

> > How often you you have to type interface names anyway, and how many of
> > those are in a shell with tab completion that takes care of it for
> > you?  
> 
> None of them are, and I don't type the names.  They require copy and
> paste, or very careful and tedious typing after looking them up.

Well, if you're scripting them, you only need to do it once per
interface, surely? That might be less work that setting up ifrename, but
use whatever works for you, your choices include, but are not restricted
to, and in no particular order.

Learn how the predictable names work
Disable the feature entirely and hope the eth0 names work as expected
Use udev rules
Use ifrename
Some combination of the above.


-- 
Neil Bothwick

...and that is how we know the Earth to be banana-shaped.

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