Re: Bug#762194: Alternative proposal for init switch on upgrades.
On Sat, Nov 29, 2014 at 11:15 PM, Tollef Fog Heen <tfheen@err.no> wrote:
> ]] Cameron Norman
>
>> On Sat, Nov 22, 2014 at 6:10 PM, Adam Borowski <kilobyte@angband.pl> wrote:
>> > On Sat, Nov 22, 2014 at 05:29:42PM -0800, Cameron Norman wrote:
>> >> I would like to propose a different one.
>> > [...]
>> >>
>> >> So, the change would be that: the sysvinit package would cease being a
>> >> transition / shim package, however it would not signal that a user
>> >> explicitly installed sysvinit; sysvinit-core would be a simple package
>> >> that just depended on sysvinit, and the presence of this package
>> >> *would* signal that the user explicitly installed sysvinit; init would
>> >> (pre-)depend on "systemd-sysv | sysvinit | sysvinit-core | upstart".
>> >
>> > I'm afraid this doesn't allow partial upgrades from wheezy to use
>> > systemd-sysv, as sysvinit is an essential package there, and apt considers
>> > packages to be essential if they're present in any source.
>>
>> I take it you mean that the user will have to remove an essential
>> package to install systemd-sysv, not that the package will not be
>> installable, correct?
>>
>> That seems reasonable to me. If the user has packages from Wheezy
>> installed, those packages could reasonably depend on sysvinit as PID 1
>> without expressing that dependency.
>
> No. They could reasonably depend on sysvinit being installed. We ship
> alternative inits in wheezy, some of which does not require sysvinit to
> be uninstalled (systemd and runit comes to mind, I would not be
> surprised if there are more).
>
> However, in the tradition of Essential packages, nowhere is it
> well-defined which of sysvinits interfaces were part of the
> essentialness and which are not. I kinda wish we'd fix that at some
> point, to make it easier to swap out (or get rid of) Essential packages.
Would systemd-sysv having a `Provides: sysvinit` fix this issue? I
think if the pre-installation /etc/inittab checking that has been
discussed is implemented then systemd could reasonably be considered
to provide sysvinit's interfaces (especially with the /dev/initctl
compatibility).
Thank you,
--
Cameron
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