udev and persistent-net.rules

udev and persistent-net.rules

[Jancs]

Dear Sirs,

I am sure the question i have is nothing new, but i cannot find an  
answer on it:

I have many DIY routers having 2 or more NICs and what drives me crazy  
is udev's
stubborn enumeration of NICs to rules or features unknown to me. So,  
every time after power cycle of after a long uptime and reboot, I get  
eth0 and eth1 swapped.

Some time ago I just trashed udev as buggy thing, but now too many  
things relies on it so I want to finally get some ideas on how to for  
udev to use enumerations I need or how to disable enumeration of NIC  
by udev to bee free to enumerate them accordind to my needs.

Regards-
Janis Eisaks

P.S. I use Slack64-13

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Re: udev and persistent-net.rules

[Andrey Borzenkov]

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On Sunday 22 of November 2009 13:53:32 Jancs wrote:
> Dear Sirs,
> 
> I am sure the question i have is nothing new, but i cannot find an
> answer on it:
> 
> I have many DIY routers having 2 or more NICs and what drives me
>  crazy is udev's
> stubborn enumeration of NICs to rules or features unknown to me. So,
> every time after power cycle of after a long uptime and reboot, I get
> eth0 and eth1 swapped.
> 
> Some time ago I just trashed udev as buggy thing, but now too many
> things relies on it so I want to finally get some ideas on how to for
> udev to use enumerations I need or how to disable enumeration of NIC
> by udev to bee free to enumerate them accordind to my needs.
> 
> Regards-
> Janis Eisaks
> 
> P.S. I use Slack64-13
> 

I do not know about your particular distribution, but stock udev creates 
rules in /etc/udev/rules.d to assign interface names based on MAC 
address, like

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:1d:09:5e:47:5b", ATTR{type}=="1", KERNEL=="eth*", 
NAME="eth0"

So if interface names change for you that could be anything of

- your distribution does not generate those rules
- those rules cannot be preserved (e.g. root is read-only, so udev 
cannot commit them to stable storage)
- interface renaming on startup does not work

One more possibility is that at some point those rules *were* generated 
but with names that you do not like.

What is wrong with using interface names as udev likes them?

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