Re: Debian boot system
Hi!
On Sat, 7 Oct 2000, Eyal Lotem wrote:
> On Sat, 07 Oct 2000, Michael Moerz wrote:
> > you will have to create an API with the functionality to add, modify and
> > delete services including defining dependencies.
> Yeap, basically, I could have a Makefile that included all the Makefiles in
> the directory, and a software package would just add Makefiles to that
> Makepool, with the virtual services and dependencies they have.
>
is nice, and ok, I would say.
> > Yeah, make will do the parallisation, but did you ever think about the
> > output of the starting services? As stated in make's info there is NO
> > guarantie that the output might get not mixed. How will you cope with that
> > by simply using make? Did you ever think about that? You would have to
> > seperate the output of the services and then to put it together again. But
> > that would create a problem when debugging unknown dependencies. I mean
> > when a failure happens in parallisation and two services are started
> > concurrently and it happens that some struggling code pieces are executed
> > together. Reproducing such events would be hardly possible due to
> > race-conditions. Debugging for the error without knowing when and what was
> > running is also impossible.
> Just cancel out the parallilism for a boot, and you know right there if it is
> the root of the problem. If it is, your dependencies are wrong. Race
> conditions might be a nightmare when programming, but when running
> shellscripts? The problems should be more trivial and less problematic,
> especially as you add redundant dependencies.
> About the log mixing: How about seperate logs for seperate daemons? Perhaps
> putting it all together as a final step of the boot process?
>
Oh, yeah, why not patch every daemon in this and that direction adding
this feature and an other, so making it impossible to run unpatched
daemons.
> > mmh, I don't want to think about the mixed output.
> Yes, I have mixed output, the dots are everywhere :) All fixable.
>
All fixable? did you ever think of missing output? Did you ever really
read the make - infopage ? I did, I know make, and I have used it to it's
best. OUTPUT might get lost, mixed and whatever. That is not desireable.
And opposing someone to boot non parallelised when having problems won't
solve them. As I stated before a way to determine when and what was
running is the only way to disolve this issue. There are no other nifty
tricks that can be played around this.
Actually I highly suggest you to read the make-infopage before you go on
telling me that it is easily fixable. You would have to redirect the
output of all services started and to put it back together for logging.
There comes in the issue that during this building of output the computer
might get hung and the last and important messages for solving the problem
might get lost. I hope I have now pointed you out at the *real* problem.
I really do not wanna turn you down nor I intend to offend your idea. I
think it's really nice having such a parallelised boot, but not when I
will loose determinisation what caused my computer to stop at boot.
--
kind regards,
Michael Moerz
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