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

[Ludovic Courtès]

Hi Carlo,

Carlo Zancanaro <address@hidden> skribis:

> On Fri, Sep 21 2018, Ludovic Courtès wrote:
>> What would you put there?  Do you have concrete examples?
>
> I would have three possible values: 'never, 'always, 'manual.
>
> 'never would mean that the service should never be restarted. This is
> for things like udev, or the filesystems, which should never be
> restarted on a running system.
>
> 'always would mean that the service is always safe to restart. I don't
> immediately know what services would fit in this category (maybe sshd,
> given Efraim's comment; maybe ntpd? I'm sure there are others). Things
> like nginx will probably not fall into this category, because they
> involve some downtime when restarting. Reloading their configuration
> (via a "reload" action, or similar) is not enough because the binary
> and/or libraries might have changed (and, in the worst case, might
> have an incompatible configuration format, although I would expect
> that to be exceedingly rare).
>
> 'manual would mean that the service should be restarted, but it need
> to be done at an appropriate time. This should prompt the user with
> the names of the services, and we should provide an option to guix
> system reconfigure to restart these services as part of the
> reconfigure. We could call the option "--restart-services".

OK, I see.

>> We can go with your patch and a message along the lines of what we
>> discussed above, and then work on the improvements you mentioned,
>> one at a time.  That way we’ll have the warm feeling of having
>> achieved something, even if there’s more to come.  :-)
>
> I won't be able to look at writing the code for this for a few weeks,
> but hopefully I'll get to it around mid- to late-October.

If that’s fine with you, I can apply the patch you initially posted so
we can start taking advantage of it (I’d like to push a Guix release by
the end of October.)  WDYT?

Thanks!

Ludo’.