[Pkg-utopia-maintainers] Bug#854801: No network after netinst Stretch RC2

[Pierre Ynard]

> >   (=> To setup a network connection I had to edit /etc/network/interfaces)

I'm confused. The installer didn't set up any network access in
/etc/network/interfaces ? Because it ran from a CD? But it detected
IPv6 nameservers on the network and installed rdnssd? Isn't networking
supposed to work anyway even if task selection doesn't install
network-manager? I'm not clear on what happened there, and what was
supposed to happen.

> This seems due to the Conflicts added in rdnssd indeed, because of:
>   https://bugs.debian.org/740998

However reports in #778492 at the time indicated that the conflict would
be resolved by removing rdnssd and installing network-manager... So I'm
surprised if we get an opposite result now.

>  2. In finish-install.d/55netcfg-copy-config, where the /e/n/i and other
>     settings copy is performed, we could check that flag and n-m's
>     status; if the flag is set and n-m wasn't installed, install rdnssd.

The scope of the problem is a bit wider than just checking for
network-manager. As it was elaborated upon above in #740998, any pair
of two network tools writing to /etc/resolv.conf without cooperation is
prone to problems. The conflict in question here was a bit of an ad-hoc
solution because both rdnssd and network-manager were automatically
started daemons likely to be pulled in a basic install.

So on one hand, adding a custom check for just network-manager is ad hoc
too and doesn't address the general problem. On the other hand, it's all
relative and if the conflict hurts more than it was supposed to help, it
could be removed too - e.g. if it's indeed what prevents network-manager
from getting installed somehow.

The recent version of the rdnssd package should be much friendlier
and more cooperative than before in managing /etc/resolv.conf when
resolvconf is not installed. The impact of running network-manager and
rdnssd concurrently should be lower than before.

I don't really believe in second-guessing the decision made by the
package manager when resolving dependencies and conflicts. But I
can suggest other options than the conflict. /etc/default/rdnssd
can be edited to disable writing to /etc/resolv.conf, or make it
conditional on network-manager, reducing rdnssd to unused reporting.
/etc/rdnssd/merge-hook can be edited to improve interaction or detect
that /etc/resolv.conf was written by network-manager.

Best regards,

-- 
Pierre Ynard
"Une âme dans un corps, c'est comme un dessin sur une feuille de papier."