LSB specification of runlevels
(Debian list policy is to not send Cc's except to people who ask for them,
by the way.)
Theodore Tso <tytso@mit.edu>:
> On Tue, Jul 03, 2001 at 11:44:49PM +0000, Lars Wirzenius wrote:
> > Given that system administrators can change and do change the meaning
> > of each runlevel, any application that makes any assumptions on the
> > meanings is simply broken.
>
> I question who many system administrators really do change the
> meanings of each runlevel.
It does happen, even if the number of people doing it isn't all that
large, compared to the total number of people running Linux. Since
customizing runlevels is allowed, and will continue to be allowed, LSB
packages can't make assumptions about and therefore the LSB shouldn't
specify the meanings.
If there really are such daemons, there needs to be some other way to
specify the dependencies instead of runlevels.
> So most distributions do assign default meanings to the runlevels,
> which are then used by the installation program to do the right thing
> when installing a particular init script.
I never said differently. In all distributions the sysadmin is still
allowed to change the meaning of each runlevel.
> Debian seems to be the one (only?) exception to this rule.
Debian defines the same default meaning to runlevels 2-5 and leaves it
to the sysadmin to customize things if they want things in another way.
Debian packages are happy with this.
> In any case, the main reason why we standardized run-levels was so
> that we could generalize this common practice in a
> distribution-nuetral way.
Since LSB packages cannot rely on the meanings, specifying them in the
standard is bad, since it gives the impression to people making LSB
packages that they can assume things. Even if the standard points out
that the runlevel meanings are just defaults and that packages can't rely
on them, the packages will do that anyway. (We've seen this countless
times with other standards.)
> (Also, I'd note that if people want to do their own weird shit things,
> there's always runlevels 7-9, which are available for local user
> customization.)
You're assuming that three runlevels is enough for customization. It isn't
always.
Don't get me wrong. I don't really care whether Debian changes its default
meanings for the runlevels or not. I will still be able to customize them
if I wish. However, I do not like the fact that the LSB over-specifies
things so that installing LSB packages onto customized setups will be
error prone.
Regarding why I wasn't around on the LSB mailing lists when these things
were discussed: the LSB is, de facto, meaningful mostly for non-free
software, and those tend to me rather little interesting to me.
--
Lars Wirzenius <liw@iki.fi>
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