bug#22039: [PATCH] 'guix system reconfigure' must start/restart/stop services

[ludo@gnu.org (Ludovic Courtès)]

Hi,

Efraim Flashner <efraim@flashner.co.il> skribis:

> On Fri, Sep 21, 2018 at 01:58:03PM +0200, Ludovic Courtès wrote:

[...]

>> Note that FHS distros don’t do better: either the service is
>> hot-replaceable (nginx; I don’t know of any other) or can at least
>> reload its config (sshd, etc.), and then it’s dynamically upgraded, or
>> it’ll be upgraded next time you restart it.
>> 
>> That’s because fundamentally only the user can tell whether now is a
>> good time to restart, say, sshd.
>
> Not exactly the point, but Debian regularly restarts sshd for me on a
> remote box (somehow) without me losing the connection.

Good point!  I think sshd opens child processes for new sessions, and
thanks to that it falls into the category of service that can be
hot-replaced.

For hot-swappable daemons, I think we should provide a specific ‘reload’
or ‘upgrade’ action as was discussed at
<https://issues.guix.info/issue/26830>.  That way, to figure out the
right strategy, we would just check whether the service supports that
action.

Thanks,
Ludo’.