Re: ANN: NetworkManager 1.2.4 released

[Dan Williams <dcbw redhat com>]

On Thu, 2016-08-04 at 22:29 +0200, Michael Biebl wrote:
> Hi
>
> Am 03.08.2016 um 18:40 schrieb Francesco Giudici:
> > The 1.2.4 release include some new features and bug fixes.
> >
> > The rc-manager option has been extended with the "symlink" and
> > "unmanaged" values. Moreover, it is now possible to set its default
> > by
> > passing the option "--with-config-dns-rc-manager-default" during
> > configuration at compile time.
>
> Given bug reports like [1], I'm tempted to switch the default in
> Debian
> from symlink to file.
> What are the benefits of symlink over file which would make it worth
> keeping?

[1] seems like a packaging issue, the symlink should probably be
removed when NM is removed.  NM can't really remove it when NM quits
because it will leave interfaces up and running and DNS is expected to
work as long as there's connectivity.

The symlink enables figuring out who's supposed to control resolv.conf
with multiple possible controllers.  For example, if systemd-networkd
is running and it owns the symlink, NM should not touch that symlink.
 Likewise for any other program.  Yes, there is resolvconf/openresolv
for some cases, but that's also been trouble over the years and
historically hasn't been able to do split DNS (though that may be
better now).

Essentially, the symlink is a hint that something else owns the file
without the user having to configure anything in NM, and without
setting +i on it which prevents the other thing that manages it from
writing to it.

Dan