Questions[runlevel](server)

So, I'm working on an upstart init script for mysql. Should be trivial, right? My stop stanza looks like:

kill timeout 30
stop on runlevel [016]

I shutdown now -r, and mysql yells about my MyISAM tables being crashed, just like I'd kill -9'd my mysql process. Boo. Upstart doesn't seem to be waiting for mysql to quit before restarting. Some searching on Google finds me this link suggesting I do, instead:

stop on starting rc RUNLEVEL=[016]

and indeed, that seems to fix the problem.

But: WFT? Essentially, I want to make sure mysql is stopped before trying to unmount the local filesystems. Is this the right way to do this? Why is my stop on runlevel stanza not waiting for mysql to stop before switching runlevels?

And: is this y'know, documented anywhere?

What do the levels in chkconfig mean?

e.g.

chkconfig --levels 235 httpd on

According to Wikipedia, 'S' is supposed to be a standard runlevel: "Single-User Mode". But if I'm not mistaken, the Single-User mode on Debian is Runlevel 1. One Debian article I found claims, that 'S' is a runlevel "that the system uses on it's way to another runlevel". Interesting...

Actually, I had always pretty much ignored this runlevel so far, but today I played around with Firestarter (yes, really, an end-user firewall) just because I was curious, which firewall rules it would generate. But then I noticed, that it creates a startup hook in /etc/rcS.d, and I wondered, if my firewall script should maybe have that, too?

Update

Now I'm even more interested in knowing what it actually is on Debian/Ubuntu, because the Shorewall package (which is a strongly "Debianized" package) also creates its (only!) startup hook in rcS.d!

I need to have only stop scripts in rcN.d (runlevels 0,1,6) for apache2. So that I always start it by myself, but when reboot occurs server will shut down apache2 properly. And when I change runlevel 2-3 server doesnt' touch apache daemon (leaving it in the state it is).

Basically, I just need a legal way to remove apache2 startup symlinks from rc2.d -> rc5.d. With tools like update-rc.d.

I can just remove those symlinks by hands, but I'm not sure if this is a proper way for this.

I have Ubuntu lucid on my home computer. Today I was experimenting with runlevels and I couldn't figure out how to change the default run level of Ubuntu. I can do that using /etc/inittab on Debian 504 but that file is not there in Ubuntu. I have searched on the web but couldn't figure out the answer.

Thanks in advance.