starting Fedora Server SIG

Les Mikesell lesmikesell at gmail.com
Fri Nov 14 01:53:43 UTC 2008


Bill Nottingham wrote:
>  
>>> HAL is an interface for querying available hardware over the system;
>>> it runs on top of d-bus. It's used by things like NetworkManager
>>> and anaconda to enumerate devices, and by the desktop systems as the
>>> underlying framework for handling PDAs, music players, hotpluggable
>>> and removable devices, etc.
>> I'd really prefer my device names to be predictable.  That is, the NIC  
>> in the same motherboard or slot position gets the same eth? name across  
>> any number of identical machines, the same controller/cable/drive-select  
>> gets the same /dev/sd? name, etc.  Is there still any way to make that  
>> happen?
> 
> By slot name or motherboard position? Not without custom udev rules,
> at this point. The biggest issue is that disk devices you have actual
> device nodes, so you can make as many /dev/disk/by-path or by-id or
> by-label symlinks that you want, without affecting something that
> wants to access it by another name.

Nearly all the machines I manage have hot-swap bays, and I want to mount 
the contents by a name related to its bay position which I know (or can 
easily be told over the phone), not by something related to the contents 
of the disk which I may not know when it is first put in place.  With 
old style scsi/sca drives this was nice and simple.   Newer machines 
with aacraid controllers already make this difficult by trying to 
logically map the newly inserted disk into the position where it was on 
some other machine.

> Since network devices don't have actual backing device nodes, they
> can only be accessed by a single name. Which makes grand unified
> device naming schemes for network hard. (Not to mention that attempting
> to get consistent motherboard or slot position out of BIOSes across
> all manufacturers is a boatload of fun.)
> 
>>  > ConsoleKit is a d-bus available daemon that tracks 'sessions' (the
>>> combination of a login and a 'seat' - a display/keyboard/mouse combo.)
>>> It's done that way because just trawling through utmp isn't the most
>>> reliable mechanism. It's used by GDM for tracking who's logged in and
>>> providing shutdown/restart functionalty, and by HAL for implementing
>>> device access for users logged in on the console.
>> Anything tied to console logins is almost certainly wrong for unattended  
>> servers that may not have anything resembling a console, or unused if  
>> they do.
> 
> .... wrong? It's not 'wrong', in the same way that tcsh isn't wrong if
> you're using bash. If someone's logged in on the console, it will be
> recorded that way.

It's wrong if you need someone at the console to start anything on a 
server and wrong if someone logging in at the console can affect 
anything the server is already doing - even things like playing audio.

-- 
    Les Mikesell
      lesmikesell at gmail.com




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