Bug#1110184: release-notes: document /etc/sysctl.conf being dropped

(I think I've fallen behind the conversation)

Samuel Plavec wrote:
> Justin B Rye <[email protected]> wrote:
>> Richard Lewis wrote:
>>> [...]
>>> there is some important package that you now need to install to get the
>>> symlink.
>>
>> That'll be linux-sysctl-defaults (Priority: important, with a
>> Recommends from systemd).
> 
> I am not sure if I understand you correctly, but that package only
> contains /usr/lib/sysctl.d/50-default.conf,
> not /etc/sysctl.conf or /etc/sysctl.d/99-sysctl.conf.

My understanding was that the reason /etc/sysctl.conf was a symlink is
that systemd doesn't read that file, so it has been deprecated for a
while; and the file in /etc has been replaced with one in /usr/lib,
because that's the usual way systemd does things - packaged defaults
go in /usr/lib/sysctl.d/, local overrides go in /etc/sysctl.d/.
Unfortunately this changeover seems to throw away any customisations
you've made, requiring you to reintroduce them in the new system.
It's a pity this didn't get a systemd NEWS.Debian entry (along with
the several trixie news items that are already in that file).
 
>> That is, we could advise users to run
>>
>>  apt list \!~i~important
>>  apt list \!~i~pstandard
> 
> On my PC, after upgrading to trixie, /etc/sysctl.conf had been removed
> (or, more precisely, it had been renamed to sysctl.conf.dpkg-bak).
> None of the packages suggested by those commands appears that it could
> have prevented that.

These are just tests that would have warned you that you needed the
new package, since the *other* problem is that you don't necessarily
get it installed on dist-upgrade (but that's bug #1099613).  If
linux-sysctl-defaults isn't installed, you end up with some even
defaultier defaults.  See

 5.1.12. Ping no longer runs with elevated privileges

for the item we already had about this particular aspect.

> (Actually, isn't there a "p" before "important" missing in the first
> command? It does not appear to work without it.)

Yes, and it gives a fairly clear error message, which tells me I
introduced that typo somewhere in the copy/pasting process.