[Resolvconf-devel] Bug#773749: Resolvconf vs wicd

[Thomas Hood]

On 14 January 2015 at 16:18, Axel Beckert <abe at debian.org> wrote:
>> It's up to the admin to change things in /etc/. Programs that play
>> around with things in /etc/ at runtime are not well behaved by Debian
>> standards.
>
> Depends. I agree for anything in the maintainer scripts, but I
> disagree for anything which can be seen as (configuration) editor.


Configuration is what the administrator does before starting a
service, not what a program does to maintain state at runtime. As the
FHS puts it:

«The /etc hierarchy contains configuration files. A "configuration
file" is a local file used to control the operation of a program; it
must be static [...].»

Configuration is thus by definition not dynamic.

The list of nameserver addresses obtained via the most recent DHCP
negotiation *is* dynamic.

Admittedly it is difficult to draw a completely sharp distinction
between configuration and state. But the idea behind it, which is
clear enough, is that it should be possible to run a Debian machine
with the root filesystem (including /etc) mounted read-only. These
issues were discussed at some length in 2003, e.g., in the following
thread.

     https://lists.debian.org/debian-devel/2003/03/msg00493.html

So as dictated by the FHS, well-behaved programs do not change files
in /etc at run time. Resolvconf was introduced in order to deal with
the exceptional case of the file /etc/resolv.conf which is under /etc
but has to be updated dynamically. In the resolvconf scheme, the
dynamic file is on another filesystem and /etc/resolv.conf itself is a
static but configurable symbolic link.
-- 
Thomas