Date: 20 Nov 1998 10:26:44 +0100 From: Benedikt Stockebrand <bs@adimus.de> To: Stephen McKay <syssgm@dtir.qld.gov.au> Cc: Bill/Carolyn Pechter <pechter@shell.monmouth.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: SysV Init Message-ID: <sa767caogtn.fsf@adimus.de> In-Reply-To: Stephen McKay's message of "Fri, 20 Nov 1998 15:46:02 %2B1000" References: <199811191220.HAA09760@shell.monmouth.com> <199811200546.PAA25250@nymph.dtir.qld.gov.au>
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Stephen McKay <syssgm@dtir.qld.gov.au> writes:
> On Thursday, 19th November 1998, Bill/Carolyn Pechter wrote:
>
> >This is one area where SysV is superior.
What's "superior"? Just additional functionality? Then it definitely
*is* superior. Easier handling? Then it's a big step in the wrong
direction. Which init is "superior" depends on your particular
needs. And SysV init has been developed to cover someones needs.
I know at least one job where a SysV init would be very handy: I'm
currently running a firewall setup on FreeBSD. I use the securelevel
kernel variable and chflags schg everything when I boot the machine.
To do actual reconfiguration things on those machines I need to reboot
them to reset the securelevel. I can't simply go into single user
mode because those boxes don't have a console or anything connected.
For maintenance I need to up an internal interface and start the sshd.
With a SysV init I'd just use a "spare" runlevel for this. Now I use
a custom rc file that checks for the existence of some "signal" files
(like the old /fastboot thing) and then runs a different set of
scripts to start the machine. But this requires to reboot the machine
every time I want
As a general rule of thumb I say that any machine that I need to
handle primarily via remote administration has good use for a "remote
administration" mode (or runlevel) in addition to the single user mode
available with the BSD init. And there are probably other cases where
a SysV init is useful. But in a "standard scenario" the SysV init
will provide no useful functionality but instead cause unnecessary
problems with its complexity.
> Woah! Put me down as absolutely against this position. Put my face on
> your dart board, if you must!
Nah, we'll have you rewrite the FreeBSD rc scripts for SysV init :-)
Actually, making a SysV init use standard BSD-style rc scripts isn't
*that* much of a problem. And I strongly propose to keep the rc
scripts BSD-style because they're usually easier to understand
especially by newcomers.
> >> I'm asking for a system where the legacy rc is there for those who want
> ^^^^^^
> "Legacy" in this case is a nasty word. It's not legacy as far as I am
> concerned. It is the current and best practice. I would be bitterly
> disappointed if it was downgraded to a compatibility option on a SysV
> style init system.
Not even a compatibility option but a special inittab that makes it
behave like a BSD init.
> >My plan was two sysctl variables for current and past run state.
> >This would avoid the need for a utmp change.
> >
> >kern.current_runlevel
> >kern.prev_runlevel
Is it necessary to mess around in the kernel for this? I'd try to
keep runlevel information within the init instead. But I admit that
I'm not comfortable enough with SysV init to know the conventions how
it provides runlevel information to regular userland programs. If no
such convention exists, why not use a Unix domain socket or such?
> I'll take the lateral view on this and assume you mean compatibility with
> existing practice. :-) I hope that any additions you make will not
> cause any *requirement* to use run levels for any purpose whatsoever.
> Optional use among consenting adults is hard to stop.
\begin{aol}Me too\end{aol}
So long,
Ben
--
Benedikt Stockebrand, Dipl. inf. Adimus Beratungsgesellschaft für System-
und Netzwerkadministration mbH & Co KG
System Administration & Design, Universitätsstr. 142, 44799 Bochum
IT Security, Remote System Mgmt Tel. (02 34) 971 971 -2, Fax -9
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