[systemd-devel] /usr vs /etc for default distro units enablement

[Colin Guthrie]

Michael Biebl wrote on 18/11/14 15:55:
> 2014-11-18 16:30 GMT+01:00 Colin Guthrie <gmane at colin.guthr.ie>:
>> Michael Biebl wrote on 18/11/14 15:09:
>>> 2014-11-18 15:59 GMT+01:00 Colin Guthrie <gmane at colin.guthr.ie>:
>>>> Didier Roche wrote on 18/11/14 13:58:
>>>>> This would be maybe a nice way for the admin to know what's coming from
>>>>> a distribution default or not. However, let's say I want to ensure that
>>>>> ssh will always be available on my server, I would (even if it's in my
>>>>> server preset) then systemctl enable openssh, no matter whatever future
>>>>> preset updates does (like disable it in the next batch upgrade).
>>>>
>>>> For the avoidance of doubt, I believe that running systemctl preset
>>>> should only ever happen on *first* install, never on upgrade or such like.
>>>>
>>>
>>> And what are you going to do, if the unit file changes?
>>> Say v1  had
>>>
>>> [Install]
>>> WantedBy=multi-user.target
>>>
>>> and version B has
>>> [Install]
>>> WantedBy=foo.target
>>
>>
>> Well this is an edge case I'm sure you'll agree.
> 
> Actually, in the short period of time (and with the currently still
> low number of packages shipping native units) in Debian, this happened
> more often then I'd have expected.
> 
> So I think we should have a better answer then just saying this is an edge case.

I still thing we should still call it an edge case tho' :)

Having a way around it is fine tho'.

>> Ultimately, with this case, doing the preset is wrong anyway. You don't
>> want the distro choice, you want the "what the user had" choice.
> 
> You only want to preservce the user choice, if it deviated from the
> distro choice. 

Well, depending on implementation that's one and the same thing. With
the current implementation of preset, they *are* the same thing, so I
think my statement is valid.

> Otherwise the package state should be updated to
> reflect the latest distro choice.

Assuming currently implementation, my script did this :)

But I can see why you'd like to encapsulate this better in a more
automated fashion and I don't have a direct answer for this (but then I
don't think the proposed scheme here covered the opposite case either -
i.e. user deviating from distro choice - so IMO it's just as bad!)

Col

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Colin Guthrie
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http://colin.guthr.ie/

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